CVE-2026-116774

Full vulnerability record from the local CVENow database.

Description

russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From 0.60.0 until 0.65.0, channel-open parsing accepts a peer-declared maximum_packet_size of zero and passes it into ChannelTx::poll_writable in russh/src/channels/io/tx.rs. The Channel::data, Channel::make_writer, and Channel::into_stream asynchronous write paths then calculate a writable size of zero and remain pending forever because window adjustments cannot satisfy a static zero packet maximum. An authenticated client can strand server writes, and a malicious server can strand client writes, allowing affected tasks, channels, and connections to accumulate without surfacing an error. This issue is fixed in version 0.65.0.

Severity

MEDIUM

CVSS score

4.3 (v3.1)

Vulnerability status

Deferred

Source identifier

[email protected]

Published

2026-10-27 21:18:05.933000

Last modified

2026-10-27 21:18:06.060000

View original CVE JSON

{
  "id": "CVE-2026-116774",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-27T21:18:05.933",
  "lastModified": "2026-10-27T21:18:06.060",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From 0.60.0 until 0.65.0, channel-open parsing accepts a peer-declared maximum_packet_size of zero and passes it into ChannelTx::poll_writable in russh/src/channels/io/tx.rs. The Channel::data, Channel::make_writer, and Channel::into_stream asynchronous write paths then calculate a writable size of zero and remain pending forever because window adjustments cannot satisfy a static zero packet maximum. An authenticated client can strand server writes, and a malicious server can strand client writes, allowing affected tasks, channels, and connections to accumulate without surfacing an error. This issue is fixed in version 0.65.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Eugeny",
          "product": "russh",
          "versions": [
            {
              "version": ">= 0.60.0, < 0.65.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-835"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/Eugeny/russh/commit/39cb9dbaa37caf555d34c6c22efa3bbbff9e186c",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/Eugeny/russh/releases/tag/v0.65.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/Eugeny/russh/security/advisories/GHSA-fw5c-8223-6h42",
      "source": "[email protected]"
    }
  ]
}