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Advisory record · GHSA-4vh2-39rq-rq8j

Vikunja: Unbounded image decode on avatar and project-background uploads enables decode/resize amplification

CVSS 7.1 HighEPSS 0.0044 · 38th percentile

Published by the GitHub Advisory Database at 9 Oct 2026, 20:52 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
code.vikunja.io/apiGo<2.6.02.6.0
Identifiers
GHSA-4vh2-39rq-rq8j · CVE-2026-91971 · GO-2026-6717
Weakness (CWE)
CWE-400
Tags
Published
9 Oct 2026
Updated
19 Oct 2026

Machine-written summary

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

Vikunja (code.vikunja.io/api) versions before 2.6.0 are affected. The avatar and project-background upload paths decode images without a pixel limit, and the avatar resize can produce a very wide output from a small extreme-aspect-ratio PNG. An authenticated user who uploads a small crafted image can drive large CPU and memory use, which repeated or concurrent requests can use to exhaust server resources. Upgrade to 2.6.0 or later. The source gives no other 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
7.1 High 4.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CNA (VulnCheck)
  • CISA KEV Not listed.
  • EPSS 0.0044, the 38th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:11 UTC First seen by agentprime
  2. 31 Oct 2026, 14:11 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.