{"id":"CVE-2026-105280","aliases":["DEBIAN-CVE-2026-105280","EEF-CVE-2026-105280","EUVD-2026-97501","GHSA-98jr-23pm-vj7c","UBUNTU-CVE-2026-105280"],"status":"published","title":"Hex writes unverified package tarballs to standard output in mix hex.package fetch","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output.\n\nHex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch.\n\nHex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.","severity":{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00211,"percentile":0.11399,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-354"],"published":"2026-10-12T15:30:14Z","modified":"2026-11-11T14:03:00Z","fixes":[{"ecosystem":"Debian:14","package":"erlang-hex","fixed_in":["2.5.3-2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:13","package":"erlang-hex","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.6-2","2.4.2-1","2.4.2-2","2.5.1-1","2.5.1-2","2.5.3-1","2.5.3-2"]},{"source":"osv","ecosystem":"Debian:14","package":"erlang-hex","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.3-2"}]}],"versions":["2.0.6-2","2.4.2-1","2.4.2-2","2.5.1-1","2.5.1-2","2.5.3-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"erlang-hex","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.5-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"erlang-hex","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.6-2build1","2.5.1-2"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"erlang-hex","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.6-2","2.0.6-2build1"]}],"products":[{"vendor":"hexpm","product":"hex"}],"references":[{"url":"https://github.com/hexpm/hex/security/advisories/GHSA-98jr-23pm-vj7c","tags":["related","vendor-advisory","advisory","report"]},{"url":"https://cna.erlef.org/cves/CVE-2026-105280.html","tags":["related","web","report"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-105280","tags":["related","web","report"]},{"url":"https://github.com/hexpm/hex/commit/d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c","tags":["related","fix","web","report"]},{"url":"https://github.com/hexpm/hex/commit/8a14632ca6ba8a8afd2a3f2098bc267c13e13d93","tags":["patch","fix","report"]},{"url":"https://github.com/hexpm/hex/commit/69489f8b74213f03db10169e6e5407e6d5fee512","tags":["patch","fix","report"]},{"url":"https://github.com","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105280.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-105280","tags":["advisory"]},{"url":"https://github.com/hexpm/hex","tags":["package"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-105280","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-105280","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-105280","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-105280","title":"Hex writes unverified package tarballs to standard output in mix hex.package fetch","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output.\n\nHex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch.\n\nHex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.","status":"published","published":"2026-10-12T15:30:14.126Z","modified":"2026-11-11T14:03:00.287Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-354"],"updated_at":"2026-11-11T15:29:20.897227Z"}],"euvd":[{"id":"EUVD-2026-97501","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output.\n\nHex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch.\n\nHex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.","status":"published","published":"2026-10-12T15:30:14Z","modified":"2026-11-11T14:03:00Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","level":"medium"}],"updated_at":"2026-11-11T15:29:13.297281Z"}],"nvd":[{"id":"CVE-2026-105280","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output.\n\nHex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch.\n\nHex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.","status":"published","published":"2026-10-12T16:17:02.68Z","modified":"2026-11-11T15:17:13.19Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/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":"medium","assessor":"secondary"}],"cwes":["CWE-354"],"updated_at":"2026-11-11T17:25:35.98892Z"}],"osv":[{"id":"CVE-2026-105280","title":"Hex writes unverified package tarballs to standard output in mix hex.package fetch","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output.\n\nHex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch.\n\nHex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.","status":"published","published":"2026-10-12T15:30:14.126Z","modified":"2026-11-12T02:30:54.790540231Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","level":"medium"}],"cwes":["CWE-354"],"updated_at":"2026-11-12T02:59:20.22065Z"},{"id":"DEBIAN-CVE-2026-105280","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output.  Hex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch.  Hex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.  This issue affects hex: from 0.20.2 before 2.5.2.","status":"published","published":"2026-10-12T16:17:02.68Z","modified":"2026-10-23T17:47:36.218419465Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/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":"medium"}],"updated_at":"2026-11-02T15:45:48.903138Z"},{"id":"EEF-CVE-2026-105280","title":"Hex writes unverified package tarballs to standard output in mix hex.package fetch","description":"## Summary\n\nImproper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that `mix hex.package fetch PACKAGE VERSION --output -` writes to standard output.\n\nHex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of `mix hex.package fetch` writes the bytes returned by `Hex.SCM.fetch/3` without that comparison, and `Hex.SCM.fetch/3` doesn't verify freshly downloaded tarballs itself. When a mirror configured with `HEX_MIRROR_URL` or `mirror_url` serves altered bytes, the command prints them and exits successfully, while the same fetch with `--output FILE` fails with a checksum mismatch.\n\nHex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the `x-hex-message` header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output.\n\nThis issue affects hex: from 0.20.2 before 2.5.2.\n\n## Details\n\n1. `mix hex.package fetch PACKAGE VERSION --output -` calls `fetch_tarball!/3`, which calls `Hex.SCM.fetch/3`.\n2. For a fresh download, `Hex.SCM.fetch/3` writes the response body to the cache and returns it without comparing it to the registry checksum.\n3. The standard output branch passes those bytes to `IO.binwrite/1`. The file and `--unpack` branches call `verify_inner_checksum!/4` and `verify_outer_checksum!/4` first.\n4. While the task runs, Hex prints messages with `Hex.Shell.info/1`, which writes to standard output. `Hex.Utils.print_error_result/1` prints the body of an error response that way; the update checker calls it when its request for `installs/hex-1.x.csv` fails, and `Hex.Registry.Server` calls it when a registry fetch fails and the cached registry is used. `Hex.HTTP` prints the `x-hex-message` warning of each response the same way. These are printed before the tarball is written, so the mirror chooses bytes that come before the tarball on standard output.\n\n## Proof of concept\n\n1. Set `HEX_MIRROR_URL` to a server that returns modified bytes for `tarballs/decimal-2.4.1.tar` and proxies everything else to repo.hex.pm.\n2. `mix hex.package fetch decimal 2.4.1 --output -` prints the modified bytes and exits 0.\n3. `mix hex.package fetch decimal 2.4.1 --output decimal.tar` fails with `Checksum mismatch against registry (outer)`.\n\n## Impact\n\nHex treats mirrors as untrusted and relies on registry signatures and checksums for package integrity. Scripts that pipe `mix hex.package fetch --output -` into another tool, such as an unpacker, a vendoring step or an installer, receive whatever the mirror served, so the mirror operator can deliver modified package contents that downstream steps treat as the published release.\n\n## Workarounds\n\nWrite the tarball to a file with `--output FILE`, which verifies the checksums, and read that file instead of standard output.\n\n## Configurations\n\nAffects `mix hex.package fetch` with `--output -` when packages are downloaded through a mirror set with `HEX_MIRROR_URL` or `mirror_url`. Downloads directly from the repository over HTTPS aren't affected unless TLS verification is broken.\n\n## Solutions\n\nUpgrade Hex to 2.5.2 or later, for example with `mix local.hex`. `mix hex.package fetch PACKAGE VERSION --output -` then verifies the registry checksum before writing the tarball to standard output and prints its messages to standard error.","status":"published","published":"2026-10-12T15:30:14.126Z","modified":"2026-10-12T15:56:08.99703007Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","level":"medium"}],"cwes":["CWE-354"],"updated_at":"2026-11-02T15:46:33.047032Z"},{"id":"UBUNTU-CVE-2026-105280","description":"Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output. Hex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch. Hex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output. This issue affects hex: from 0.20.2 before 2.5.2.","status":"published","published":"2026-10-12T16:17:00Z","modified":"2026-10-28T17:50:30Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:55:59.130573Z"}]}}