Russh SSH message fields were decoded through allocation-first parsers before field-specific bounds

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-48110: 0.37% estimated exploitation activity in the next 30 days; percentile 30.59 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

SSH message fields were decoded through allocation-first parsers before field-specific bounds Summary Several russh client and server message handlers decoded attacker-controlled SSH strings, name-lists, and byte fields into owned allocations before applying field-specific bounds. A remote SSH peer could send oversized, high-fanout, or malformed length-prefixed fields and make the library allocate, attempt to allocate, or split data before rejecting input that should have been rejected earlier. Affected Versions Oldest verified exploitable stable release: russh 0.34.0. - Historical stronger case: russh = 0.34.0, < 0.58.0. These releases have the allocation-first KEXINIT field parsing issue and still use CryptoVec for inbound packet/decompression buffers. A peer can combine negotiated RFC zlib, rekey, compressed KEXINIT expansion, historical CryptoVec decompression growth, and KEXINIT name-list fanout. - Current maintained-line case: russh = 0.58.0, including 0.60.2. These releases…

Published by the source

11 Jun 2026, 20:33 UTC

Last modified by the source

11 Jun 2026, 20:33 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4r3c-5hpg-58qr

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# Patch Next advisory brief: CVE-2026-48110

Advisory: Russh SSH message fields were decoded through allocation-first parsers before field-specific bounds
IDs: CVE-2026-48110, GHSA-4r3c-5hpg-58qr
Record: https://patchnext.com/advisories/cve-2026-48110 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: russh 0.61.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io russh: affected >= 0.34.0, < 0.61.0; fixed in 0.61.0

## Suggested inspection (read-only)
- crates.io russh: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on russh.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4r3c-5hpg-58qr (GitHub-reviewed advisory GHSA-4r3c-5hpg-58qr lists affected ranges: crates.io russh >=0.34.0 <0.61.0)

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