CVE catalog

CVE-2023-3603

libssh affected and fixed versions

A missing allocation check in sftp server processing read requests may cause a NULL dereference on low-memory conditions. The malicious client can request up to 4GB SFTP reads, causing allocation of up to 4GB buffers, which was not being checked for failure. This will likely crash the authenticated user's sftp server connection (if implemented as forking as recommended). For thread-based servers, this might also cause DoS for legitimate users. Given this code is not in any released versions, no security releases have been issued.

Severity: Low · CVSS 3.1CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Published: Jul 10, 2023, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 0.90% · Oct 27, 2026

Projects and upstream resources

[libssh][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Version impact has not been established. The original provider fields are retained below.

Provider details and historical evidence

Original provider fields

{
  "package_releases": [
    {
      "name": "libssh",
      "status": "not affected",
      "release": "sid",
      "version": "0.12.2-1"
    },
    {
      "name": "libssh",
      "status": "not affected",
      "release": "forky",
      "version": "0.12.2-1"
    },
    {
      "name": "libssh",
      "status": "not affected",
      "release": "trixie",
      "version": "0.11.5-0+deb13u1"
    },
    {
      "name": "libssh",
      "status": "not affected",
      "release": "trixie-security",
      "version": "0.11.5-0+deb13u1"
    },
    {
      "name": "libssh",
      "status": "not affected",
      "release": "bookworm",
      "version": "0.10.6-0+deb12u2"
    },
    {
      "name": "libssh",
      "status": "not affected",
      "release": "bookworm-security",
      "version": "0.10.6-0+deb12u3"
    }
  ],
  "fixed_versions": [
    {
      "bug": null,
      "name": "libssh",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "unimportant",
      "fixed_version": "0"
    },
    {
      "bug": null,
      "name": "libssh",
      "type": "source",
      "origin": null,
      "release": "forky",
      "urgency": "unimportant",
      "fixed_version": "0"
    },
    {
      "bug": null,
      "name": "libssh",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "unimportant",
      "fixed_version": "0"
    },
    {
      "bug": null,
      "name": "libssh",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "unimportant",
      "fixed_version": "0"
    }
  ],
  "distribution_packages": []
}

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[libssh-4]Unknown
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
[libssh-dev]Unknown
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
[libssh-doc]Unknown
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · all · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u2 · all · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · all · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · all · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
[libssh-gcrypt-4]Unknown
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
[libssh-gcrypt-dev]Unknown
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Not affected
  dsa · libssh · debian · bookworm

Observed: Oct 28, 2026, 5:44:57 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]