{"id":"CVE-2024-31497","aliases":["ALPINE-CVE-2024-31497","DEBIAN-CVE-2024-31497","DLA-3839-1","EUVD-2024-29377","GHSA-6p4c-r453-8743","MGASA-2024-0140","UBUNTU-CVE-2024-31497","openSUSE-SU-2024:0111-1","openSUSE-SU-2024:13868-1","openSUSE-SU-2024:13870-1"],"status":"published","title":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to...","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.05726,"percentile":0.93098,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":true},"cwes":["CWE-338"],"published":"2024-04-15T00:00:00Z","modified":"2026-11-03T06:32:45Z","exploits":[{"source":"pocgithub","id":"edutko/cve-2024-31497","title":"edutko/cve-2024-31497","date":"2024-04-17","url":"https://github.com/edutko/cve-2024-31497"},{"source":"pocgithub","id":"sh1k4ku/CVE-2024-31497","title":"sh1k4ku/CVE-2024-31497","date":"2024-04-17","url":"https://github.com/sh1k4ku/CVE-2024-31497"},{"source":"pocgithub","id":"HugoBond/CVE-2024-31497-POC","title":"HugoBond/CVE-2024-31497-POC","date":"2024-05-10","url":"https://github.com/HugoBond/CVE-2024-31497-POC"},{"source":"pocgithub","id":"LukaWynants/Onderzoek_CVE-2024-31497-POC","title":"LukaWynants/Onderzoek_CVE-2024-31497-POC","date":"2025-10-16","url":"https://github.com/LukaWynants/Onderzoek_CVE-2024-31497-POC"}],"fixes":[{"ecosystem":"Alpine:v3.16","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.17","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.18","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.19","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"putty","fixed_in":["0.81-r0"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"filezilla","fixed_in":["3.67.0-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"filezilla","fixed_in":["3.67.0-1"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"putty","fixed_in":["0.78-2+deb12u2"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"putty","fixed_in":["0.81-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"putty","fixed_in":["0.81-1"],"sources":["osv"]},{"ecosystem":"Debian:10","package":"putty","fixed_in":["0.74-1+deb11u1~deb10u2"],"sources":["osv"]},{"ecosystem":"Mageia:9","package":"putty","fixed_in":["0.81-1.mga9"],"sources":["osv"]},{"ecosystem":"Mageia:9","package":"filezilla","fixed_in":["3.67.0-1.mga9"],"sources":["osv"]},{"ecosystem":"Mageia:9","package":"libfilezilla","fixed_in":["0.47.0-1.mga9"],"sources":["osv"]},{"ecosystem":"SUSE:Package 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PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T00:00:00Z","modified":"2025-11-04T22:06:12.533Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"adp"}],"cwes":["CWE-338"],"updated_at":"2026-11-02T14:34:13.991836Z"}],"euvd":[{"id":"EUVD-2024-29377","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T00:00:00Z","modified":"2025-11-04T22:06:12Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T19:49:20.707326Z"}],"ghsa":[{"id":"GHSA-6p4c-r453-8743","title":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to...","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. One scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. Because SSH is sometimes used to authenticate to Git services, it is possible that this vulnerability could be leveraged for supply-chain attacks on software maintained in Git. It is also conceivable that signed messages from PuTTY or Pageant are readable by adversaries more easily in other scenarios, but none have yet been disclosed.","status":"published","published":"2024-04-15T21:30:46Z","modified":"2024-04-17T00:31:29Z","updated_at":"2026-11-02T14:57:12.929787Z"}],"nvd":[{"id":"CVE-2024-31497","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T20:15:11.077Z","modified":"2026-06-17T07:28:32.987Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-338"],"updated_at":"2026-11-02T14:09:50.299382Z"}],"osv":[{"id":"ALPINE-CVE-2024-31497","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T20:15:11.077Z","modified":"2026-11-03T06:32:45.543442146Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T07:17:02.90744Z"},{"id":"CVE-2024-31497","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T20:15:11.077Z","modified":"2026-04-16T04:35:22.021842976Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:40.06138Z"},{"id":"DEBIAN-CVE-2024-31497","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T20:15:11.077Z","modified":"2026-11-02T12:01:45.316031041Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:42.530184Z"},{"id":"UBUNTU-CVE-2024-31497","description":"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.","status":"published","published":"2024-04-15T20:15:00Z","modified":"2025-10-24T05:09:09Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T16:54:48.333535Z"},{"id":"DLA-3839-1","title":"putty - security update","status":"published","published":"2024-06-20T00:00:00Z","modified":"2026-03-09T01:21:29.910648Z","updated_at":"2026-11-02T15:46:12.203458Z"},{"id":"MGASA-2024-0140","title":"Updated putty \u0026 filezilla packages fix security vulnerability","description":"The PuTTY client and all related components generate heavily biased\nECDSA nonces in the case of NIST P-521. To be more precise, the first 9\nbits of each ECDSA nonce are zero. This allows for full secret key\nrecovery in roughly 60 signatures by using state-of-the-art techniques.\nThese signatures can either be harvested by a malicious server\n(man-in-the-middle attacks are not possible given that clients do not\ntransmit their signature in the clear) or from any other source, e.g.\nsigned git commits through forwarded agents. The nonce generation for\nother curves is slightly biased as well. However, the bias is negligible\nand far from enough to perform lattice-based key recovery attacks (not\nconsidering cryptanalytical advancements).\n","status":"published","published":"2024-04-20T18:11:17Z","modified":"2026-04-16T04:41:31.962257371Z","updated_at":"2026-11-02T15:49:42.684501Z"},{"id":"openSUSE-SU-2024:0111-1","title":"Security update for putty","description":"This update for putty fixes the following issues:\n\nUpdate to release 0.81\n\n* Fix CVE-2024-31497: NIST P521 / ecdsa-sha2-nistp521 signatures are no longer\n  generated with biased values of k. The previous bias compromises private keys.\n","status":"published","published":"2024-04-19T12:53:10Z","modified":"2026-02-04T02:51:52.227084Z","updated_at":"2026-11-02T16:58:33.135986Z"},{"id":"openSUSE-SU-2024:13868-1","title":"putty-0.81-1.1 on GA media","description":"These are all security issues fixed in the putty-0.81-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T04:13:28.935005Z","updated_at":"2026-11-02T16:58:36.662953Z"},{"id":"openSUSE-SU-2024:13870-1","title":"filezilla-3.67.0-1.1 on GA media","description":"These are all security issues fixed in the filezilla-3.67.0-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T03:29:59.346293Z","updated_at":"2026-11-02T16:58:36.662953Z"}]}}