# CVE-2026-116775: pageant: unbounded frame buffering on peer-controlled 4-byte length prefix (memory-exhaustion DoS)

Status: published. Published: 2026-10-27. Updated: 2026-11-03.

pageant provides a PageantStream type that implements AsyncRead and AsyncWrite traits and can be used to communicate with a running Pageant instance. From 0.2.0 until 0.2.5, PageantStream::new in pageant/src/wmmessage.rs trusts a peer-controlled four-byte length prefix and buffers until len + 4 bytes are available without checking the fixed _AGENT_MAX_MSGLEN transport capacity. An application that bridges an SSH forwarded-agent channel to the raw stream can allow a malicious server to force large allocations or retain a partially filled frame, causing client memory exhaustion. This issue is fixed in version 0.2.5.

## Remediation

- fix: pageant (crates.io): OSV reports a fixed version 0.2.5. Check the advisory for supported release branches. (source: OSV GHSA-662x-8wvj-2276) — https://github.com/advisories/GHSA-662x-8wvj-2276

## Affected products and versions

- Eugeny / russh: >= 0.2.0, < 0.2.5 (affected). Source: CNA: GitHub_M
-  / pageant (pageant): ≥ 0.2.0; < 0.2.5 (affected, semver); OSV events: introduced 0.2.0; fixed 0.2.5. Source: OSV GHSA-662x-8wvj-2276

## Severity and prioritization

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: 0.29% as of 2026-11-02; percentile 22.01%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-770

## Exploit evidence

- exploit: https://github.com/Eugeny/russh/security/advisories/GHSA-662x-8wvj-2276 (ADP: CISA-ADP)

## References

- https://github.com/Eugeny/russh/security/advisories/GHSA-662x-8wvj-2276 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/Eugeny/russh/commit/69e4b55513eaa8ac9d2ad4236f13171fc164e10a (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/Eugeny/russh/releases/tag/v0.65.0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/Eugeny/russh/security/advisories/GHSA-662x-8wvj-2276 (ADP: CISA-ADP; exploit)

- https://github.com/advisories/GHSA-662x-8wvj-2276 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-662x-8wvj-2276 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-116775; retrieved 2026-11-03; source updated 2026-11-03

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-662x-8wvj-2276; retrieved 2026-11-03; source updated 2026-10-30

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116775; retrieved 2026-11-03; source updated Not reported

Revision: 63145a27d0d767c903da5e716780a0a4a4ead4ca5e280891b377cd76e9ac906b

Canonical: https://y2.dev/cve/CVE-2026-116775

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.