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Advisory record · GHSA-4xjf-493q-98p3

Gitea SSH Key Parser Denial of Service

CVSS 6.2 MediumEPSS 0.0017 · 6th percentile

Published by the GitHub Advisory Database at 21 Jul 2026, 21:09 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
code.gitea.io/giteaGo<1.27.01.27.0
gitea.devGo<1.27.01.27.0
Identifiers
GHSA-4xjf-493q-98p3 · CVE-2026-56657 · GO-2026-6042
Weakness (CWE)
CWE-284 · CWE-400
Tags
Published
21 Jul 2026
Updated
24 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Gitea versions before 1.27.0 (packages code.gitea.io/gitea and gitea.dev) are vulnerable to a denial of service when parsing SSH public keys in RFC 4716 format. An authenticated user can submit a very large key with many short lines, causing quadratic processing work that can exhaust server CPU and memory and take the instance offline. Upgrade to version 1.27.0 or later. The source gives no workaround.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
6.2 Medium 3.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H GitHub Advisory Database
  • CISA KEV Not listed.
  • EPSS 0.0017, the 6th percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:13 UTC First seen by agentprime
  2. 31 Oct 2026, 14:13 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.