{"id":"CVE-2026-16317","aliases":["EUVD-2026-46399","GHSA-684c-v35q-fvx7","SUSE-SU-2026:5101-1","openSUSE-SU-2026:11492-1","openSUSE-SU-2026:11526-1","openSUSE-SU-2026:21474-1","openSUSE-SU-2026:21501-1"],"status":"published","title":"Silent Drop of TLS 1.3 Encrypted Records in s2n-tls","description":"Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. \n\n\n\nThis enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write.\n\n\n\nAll TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6","severity":{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00186,"percentile":0.08307,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-354"],"published":"2026-07-21T20:12:48Z","modified":"2026-11-05T13:27:13Z","affected":[{"source":"osv","ecosystem":"SUSE:Linux Enterprise Module for Public Cloud 15 SP6","package":"aws-efs-utils","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.4-150600.17.12.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Module for Public Cloud 15 SP7","package":"aws-efs-utils","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.4-150600.17.12.1"}]}],"bundled":3},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"aws-efs-utils","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.2.0-1.1"}]}],"bundled":3},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"s2n","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.7.7-1.1"}]}],"bundled":2},{"source":"osv","ecosystem":"openSUSE:Leap 16.0","package":"s2n","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.1-bp160.2.1"}]}],"bundled":2}],"products":[{"vendor":"aws","product":"s2n-tls"}],"references":[{"url":"https://github.com/aws/s2n-tls/releases/tag/v1.7.6","tags":["release-notes","patch","fix"]},{"url":"https://aws.amazon.com/security/security-bulletins/2026-062-aws/","tags":["vendor-advisory","advisory"]},{"url":"https://github.com/aws/s2n-tls/security/advisories/GHSA-684c-v35q-fvx7","tags":["release-notes","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/16xxx/CVE-2026-16317.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-16317","tags":["advisory"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-20265101-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1263683","tags":["report"]},{"url":"https://bugzilla.suse.com/1272349","tags":["report"]},{"url":"https://bugzilla.suse.com/1272354","tags":["report"]},{"url":"https://bugzilla.suse.com/1274202","tags":["report"]},{"url":"https://bugzilla.suse.com/1275449","tags":["report"]},{"url":"https://bugzilla.suse.com/1275450","tags":["report"]},{"url":"https://bugzilla.suse.com/1281947","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2026-16317","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-16318","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-25541","tags":["web"]},{"url":"","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1272352","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-16317","title":"Silent Drop of TLS 1.3 Encrypted Records in s2n-tls","description":"Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. \n\n\n\nThis enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write.\n\n\n\nAll TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6","status":"published","published":"2026-07-21T20:12:48.047Z","modified":"2026-07-22T19:41:19.156Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-354"],"updated_at":"2026-11-02T14:20:10.870108Z"}],"euvd":[{"id":"EUVD-2026-46399","description":"Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. \n\n\n\nThis enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write.\n\n\n\nAll TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6","status":"published","published":"2026-07-21T20:12:48Z","modified":"2026-07-22T19:41:19Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N","level":"high"}],"updated_at":"2026-11-02T18:19:44.433437Z"}],"nvd":[{"id":"CVE-2026-16317","description":"Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. \n\n\n\nThis enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write.\n\n\n\nAll TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6","status":"published","published":"2026-07-21T21:16:49.06Z","modified":"2026-10-24T19:10:00.127Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-354"],"updated_at":"2026-11-02T14:12:31.394335Z"}],"osv":[{"id":"CVE-2026-16317","title":"Silent Drop of TLS 1.3 Encrypted Records in s2n-tls","description":"Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. \n\n\n\nThis enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write.\n\n\n\nAll TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6","status":"published","published":"2026-07-21T20:12:48.047Z","modified":"2026-11-05T13:27:13.699493706Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N","level":"high"}],"cwes":["CWE-354"],"updated_at":"2026-11-05T16:37:45.64821Z"},{"id":"openSUSE-SU-2026:11492-1","title":"aws-efs-utils-3.2.0-1.1 on GA media","description":"These are all security issues fixed in the aws-efs-utils-3.2.0-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-08-11T00:00:00Z","modified":"2026-08-12T10:45:07.13203099Z","updated_at":"2026-11-02T16:58:39.516824Z"},{"id":"openSUSE-SU-2026:11526-1","title":"libs2n1-1.7.7-1.1 on GA media","description":"These are all security issues fixed in the libs2n1-1.7.7-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-08-15T00:00:00Z","modified":"2026-08-16T11:45:05.557675656Z","updated_at":"2026-11-02T16:58:39.516824Z"},{"id":"openSUSE-SU-2026:21474-1","title":"Security update for s2n","description":"This update for s2n fixes the following issues:\n\nChanges in s2n:\n\n- CVE-2026-16318: Denial of Service due to memory leak in QUIC\n  transport parameters handler (bsc#1272352)\n- CVE-2026-16317: man-in-the-middle attack can silently discard\n  individual application data records\n","status":"withdrawn","published":"2026-07-28T15:14:50Z","modified":"2026-07-31T14:01:33.622023341Z","updated_at":"2026-11-02T16:58:41.885092Z"},{"id":"openSUSE-SU-2026:21501-1","title":"Security update for s2n","description":"This update for s2n fixes the following issues:\n\nChanges in s2n:\n\n- CVE-2026-16318: Denial of Service due to memory leak in QUIC\n  transport parameters handler (bsc#1272352)\n- CVE-2026-16317: man-in-the-middle attack can silently discard\n  individual application data records\n","status":"published","published":"2026-07-29T09:24:11Z","modified":"2026-07-31T18:24:09.693637563Z","updated_at":"2026-11-02T16:58:41.885092Z"},{"id":"SUSE-SU-2026:5101-1","title":"Security update for aws-efs-utils","description":"This update for aws-efs-utils fixes the following issues:\n\nSecurity issues fixed:\n\n- CVE-2026-16317: s2n-tls: man-in-the-middle attack can silently discard individual application data records\n  (bsc#1272354).\n- CVE-2026-16318: s2n-tls: Denial of Service due to memory leak in QUIC transport parameters handler (bsc#1272349).\n- CVE-2026-25541: bytes: integer overflow in 'BytesMut:reserve' can lead to undefined behavior and crashes\n  (bsc#1274202).\n\nChanges for aws-efs-utils:\n\n- Update to version 3.3.4\n","status":"published","published":"2026-11-04T18:01:29Z","modified":"2026-11-05T13:15:07.550193736Z","updated_at":"2026-11-05T13:30:00.949926Z"}]}}