Vikunja before 2.7.1 Memory Exhaustion DoS via Unbounded Image Decodes
Vikunja up to and including 2.7.0 is affected through avatar and project background image uploads. The fix is in 2.7.1. CVSS rates it High (7.1).
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 2.7.1
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affected: Vikunja versions up to and including 2.7.0 (fixed in 2.7.1) Affects avatar upload, OIDC avatar and project background upload paths, which decode images without a concurrency bound
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.31% · 23rd percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 15/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Vikunja, a task management application, is affected by a flaw in how its avatar and background image uploads are processed. An attacker with a low-privilege user account can reach it remotely over the network by sending several parallel, tiny but highly compressible PNG uploads that decode into very large images, which can exhaust server memory and crash the API process.
Read the original description
Vikunja before 2.7.1 contains an uncontrolled resource consumption vulnerability that allows authenticated users to exhaust server memory through concurrent image decodes in avatar and background uploads. Attackers can send several parallel tiny, highly compressible PNGs decoded at up to 50 megapixels each, pushing the API process into memory pressure or an OOM kill.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.1/10CVSS 7.1
- No patch0/5No signal
What would change the score
- Would score about 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 22 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Affected: Vikunja versions up to and including 2.7.0 (fixed in 2.7.1) Affects avatar upload, OIDC avatar and project background upload paths, which decode images without a concurrency boundUpgrade to a fixed version: 2.7.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- go-vikunja vikunja
fixed in 2.7.1
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123501
Is CVE-2026-123501 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The avatar upload, OIDC avatar and project background upload paths decode images without limiting how many decodes run at once. A handful of parallel uploads by an authenticated user can push the API process into memory pressure or an out-of-memory kill, which denies service.Source: github.com
Which versions are affected by CVE-2026-123501?
vikunja: before 2.7.1.Source: cve.now feed data
Am I affected, and how do I check?
Vikunja versions up to and including 2.7.0 are affected, in the avatar upload, OIDC avatar and project background upload paths. Check the Vikunja version your server runs against that range.Source: github.com
How do I fix CVE-2026-123501?
Upgrade Vikunja to 2.7.1 or later, which contains the fix. The advisory lists no workaround.Source: github.com