Vulnerability-Lookup

UBUNTU-CVE-2026-116773 (CVE-2026-116773)

Vulnerability from osv_ubuntu – Published: 2026-10-27 21:18 – Updated: 2026-10-27 21:18 – Source website

Details

russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repeated packets encoded with russh's private msg::EXT_INFO = 7 before authentication, while the standards-compliant EXT_INFO message number 82 does not reach the affected handler. The handle_ext_info function appends every parsed extension name to received_extensions without clearing, deduplicating, or bounding the vector. A malicious SSH server that deliberately sends private message number 7 can therefore retain an unbounded number of attacker-controlled extension names for the session lifetime, causing progressive client memory exhaustion. This issue is fixed in version 0.65.0.

Severity

4.3 (Medium)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-116773	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-116773	REPORT
	https://github.com/Eugeny/russh/security/advisori…	REPORT
	https://github.com/Eugeny/russh/commit/b33e93beec…	REPORT
	https://github.com/Eugeny/russh/releases/tag/v0.65.0	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "librust-russh-dev",
            "binary_version": "0.57.1-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "rust-russh",
        "purl": "pkg:deb/ubuntu/rust-russh@0.57.1-2?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.57.1-2"
      ]
    }
  ],
  "aliases": [],
  "details": "russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repeated packets encoded with russh\u0027s private msg::EXT_INFO = 7 before authentication, while the standards-compliant EXT_INFO message number 82 does not reach the affected handler. The handle_ext_info function appends every parsed extension name to received_extensions without clearing, deduplicating, or bounding the vector. A malicious SSH server that deliberately sends private message number 7 can therefore retain an unbounded number of attacker-controlled extension names for the session lifetime, causing progressive client memory exhaustion. This issue is fixed in version 0.65.0.",
  "id": "UBUNTU-CVE-2026-116773",
  "modified": "2026-10-27T21:18:00Z",
  "published": "2026-10-27T21:18:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-116773"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-116773"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/Eugeny/russh/security/advisories/GHSA-4p9f-7p9m-5vfg"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/Eugeny/russh/commit/b33e93beec393e6d29eee69c1b8831736724ee75"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/Eugeny/russh/releases/tag/v0.65.0"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-116773"
  ]
}

CVE-2026-116773 (GCVE-0-2026-116773)

Vulnerability from cvelistv5 – Published: 2026-10-27 20:23 – Updated: 2026-10-30 15:17

Title

russh's SSH client is susceptible to unbounded allocations via EXT_INFO packets

Summary

Severity

4.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-30 15:17 UTC

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7886 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/Eugeny/russh/security/advisori…	x_refsource_CONFIRM
https://github.com/Eugeny/russh/commit/b33e93beec…	x_refsource_MISC
https://github.com/Eugeny/russh/releases/tag/v0.65.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
Eugeny	russh	Affected: < 0.65.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-116773",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-30T15:17:39.066575Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-30T15:17:49.289Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/Eugeny/russh/security/advisories/GHSA-4p9f-7p9m-5vfg"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "russh",
          "vendor": "Eugeny",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.65.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repeated packets encoded with russh\u0027s private msg::EXT_INFO = 7 before authentication, while the standards-compliant EXT_INFO message number 82 does not reach the affected handler. The handle_ext_info function appends every parsed extension name to received_extensions without clearing, deduplicating, or bounding the vector. A malicious SSH server that deliberately sends private message number 7 can therefore retain an unbounded number of attacker-controlled extension names for the session lifetime, causing progressive client memory exhaustion. This issue is fixed in version 0.65.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-27T20:23:47.305Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/Eugeny/russh/security/advisories/GHSA-4p9f-7p9m-5vfg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/Eugeny/russh/security/advisories/GHSA-4p9f-7p9m-5vfg"
        },
        {
          "name": "https://github.com/Eugeny/russh/commit/b33e93beec393e6d29eee69c1b8831736724ee75",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Eugeny/russh/commit/b33e93beec393e6d29eee69c1b8831736724ee75"
        },
        {
          "name": "https://github.com/Eugeny/russh/releases/tag/v0.65.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Eugeny/russh/releases/tag/v0.65.0"
        }
      ],
      "source": {
        "advisory": "GHSA-4p9f-7p9m-5vfg",
        "discovery": "UNKNOWN"
      },
      "title": "russh\u0027s SSH client is susceptible to unbounded allocations via EXT_INFO packets"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-116773",
    "datePublished": "2026-10-27T20:23:25.559Z",
    "dateReserved": "2026-10-26T21:53:35.165Z",
    "dateUpdated": "2026-10-30T15:17:49.289Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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