CVE-2026-91971: vikunja · Uncontrolled Resource Consumption
Affects vikunjaSource CVE Database V5
Not known to be exploited · CVSS 7.1 High : upgrade to 2.6.0 soon.
Data as of 31 Oct 2026, 08:20 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.6.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade vikunja and github.com/go-vikunja/vikunja to 2.6.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| go-vikunjavikunja | Affected
| Fixed in
|
Gogithub.com/go-vikunja/vikunjapkg:golang/github.com/go-vikunja/vikunjaOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
The recommended fix is to apply pixel-dimension caps similar to those on the task-attachment preview path to the avatar and project background decode paths, and to bound both the width and height of resized images. If you cannot patch yet, administrators should consider limiting upload sizes or disabling avatar and background image uploads if feasible.
Description
### Summary The 50-megapixel decode guard exists only on the task-attachment preview path. Avatar and project-background uploads decode uploaded images with no pixel cap. Worse, the avatar resize fixes the output height at 1024 and derives the width from the aspect ratio, so a tiny extreme-aspect-ratio PNG expands to an enormous output image — an input-side pixel cap would not catch it. ### Details The only `maxPixels` check (50MP) is in `TaskAttachment.GetPreview` (`pkg/models/task_attachment.go` ~lines 332-338). No such check guards: - avatar upload: `pkg/modules/avatar/upload/upload.go` (~lines 82, 137, 141) - project background: `pkg/modules/background/handler/background.go` (~lines 174, 269, 289) `imaging.Resize(img, 0, 1024, imaging.Lanczos)` (upload.go ~line 141) fixes height=1024 and derives width from the aspect ratio: a 20000x10 input yields a ~2,048,000 x 1024 output (~2.1 billion pixels), so a few-hundred-byte file drives huge CPU and memory. ### PoC (verified at runtime against v2.5.0) ``` PUT /api/v1/user/settings/avatar/upload avatar=8000x8000 PNG (64MP, 192KB) -> 200 (accepted; exceeds the 50MP attachment cap) PUT /api/v1/user/settings/avatar/upload avatar=20000x10 PNG (681 bytes) -> 200 after ~19.6s of server processing ``` Contrast (guard present): uploading the 64MP PNG as a task attachment and requesting its preview returns in ~1ms without decoding — `GetPreview` rejects it via `maxPixels` and falls back to the raw file. ### Impact A small crafted upload drives disproportionate CPU and memory on the avatar and background paths. Repeated or concurrent requests can exhaust server resources. Amplification comes from both the missing input pixel cap and the height-fixed resize, so an input-side cap alone is insufficient. ### Fix Apply a pixel-dimension cap (as on the attachment path) to the avatar and background decode paths, and bound the resize output dimensions (cap width as well as height).