CVE-2026-91971

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-15. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 6.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Vikunja before 2.6.0 fails to apply pixel decode limits to avatar and project-background upload endpoints, allowing authenticated users to upload crafted images that decode to excessive pixel counts. Attackers can upload small images with extreme aspect ratios that consume significant CPU and memory during processing, causing denial of service through repeated or concurrent uploads.

CVSS v3
6.5
EG Score
6.5MEDIUMhigh confidence
EG Risk
45
EG Risk 45/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
The EG Score, 6.5 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
35th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 15, 2026

Last Modified

September 21, 2026

Advisory Details (2)

Auto-updated Sep 15, 2026
Patch available. Sources: github.
Web page

Vikunja before 2.6.0 Denial of Service via Avatar Upload | Advisories | VulnCheck

https://www.vulncheck.com/advisories/vikunja-before-2.6.0-denial-of-service-via-avatar-upload
GitHub advisoryMentions a patch (unverified)

Unbounded image decode on avatar and project-background uploads enables decode/resize amplification · Advisory · go-vikunja/vikunja · GitHub

https://github.com/go-vikunja/vikunja/security/advisories/GHSA-4vh2-39rq-rq8j

Vendor Advisories for CVE-2026-91971(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFix by version rangeDependents
code.vikunja.io/api—
  • every version up to 2.6.0: fixed in 2.6.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 23× in last 7d / 81× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 82 is merged into the row it repeats.

  1. 2026-10-11 19:13 UTCEG score recompute
  2. 2026-10-11 16:29 UTCEG score recompute
  3. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  4. 2026-10-11 13:44 UTCEG score recompute
  5. 2026-10-10 22:55 UTCEG score recompute
  6. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  7. 2026-10-09 23:53 UTCEG score recompute
  8. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  9. 2026-10-09 02:11 UTCEG score recompute
  10. 2026-10-09 02:10 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  11. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-10-08 04:29 UTCEG score recompute
  13. 2026-10-08 04:29 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-10-07 06:48 UTCEG score recompute
  16. 2026-10-07 06:48 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  17. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-10-06 09:06 UTCEG score recompute
  19. 2026-10-06 09:06 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  20. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  21. 2026-10-05 11:25 UTCEG score recompute
  22. 2026-10-05 11:25 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  23. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  24. 2026-10-04 13:43 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  25. 2026-10-03 16:02 UTCEG score recompute
Show 56 more
  1. 2026-10-03 16:02 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  2. 2026-10-02 18:18 UTCEG score recompute
  3. 2026-10-02 18:17 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  4. 2026-10-01 20:33 UTCEG score recompute
  5. 2026-10-01 20:33 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  6. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  7. 2026-09-30 22:51 UTCEG score recompute
  8. 2026-09-30 22:51 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  9. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-09-30 01:10 UTCEG score recompute
  11. 2026-09-30 01:10 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  12. 2026-09-29 01:11 UTCEG score recompute
  13. 2026-09-29 01:11 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  14. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-09-28 03:23 UTCEG score recompute
  16. 2026-09-28 03:23 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  17. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-09-27 05:42 UTCEG score recompute
  19. 2026-09-27 05:42 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  20. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  21. 2026-09-26 08:00 UTCEG score recompute
  22. 2026-09-26 08:00 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  23. 2026-09-25 10:18 UTCEG score recompute
  24. 2026-09-25 10:18 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  26. 2026-09-24 12:37 UTCEG score recompute
  27. 2026-09-24 12:37 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  28. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  29. 2026-09-23 14:55 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  30. 2026-09-22 17:13 UTCEG score recompute
  31. 2026-09-22 17:13 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  32. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  33. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  34. 2026-09-21 19:31 UTCEG score recompute
  35. 2026-09-21 19:31 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  36. 2026-09-21 18:55 UTCEG score recompute
  37. 2026-09-21 18:55 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  38. 2026-09-21 10:11 UTCEG score recompute
  39. 2026-09-21 10:11 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  40. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  41. 2026-09-20 12:30 UTCEG score recompute
  42. 2026-09-20 12:30 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  43. 2026-09-19 14:48 UTCEG score recompute
  44. 2026-09-19 14:48 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  45. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  46. 2026-09-18 17:06 UTCEG score recompute
  47. 2026-09-18 17:06 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  48. 2026-09-17 19:32 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  49. 2026-09-17 19:22 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  50. 2026-09-16 21:07 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  51. 2026-09-16 14:14 UTCEG score recompute
  52. 2026-09-16 14:14 UTCGHSA enrichmentGHSA-69rj-q3v9-vffp · GitHub severity HIGH · GitHub CVSS 6.5
  53. 2026-09-16 14:09 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  54. 2026-09-15 16:32 UTCEG score recompute
  55. 2026-09-15 15:23 UTCEG score recomputeFirst assessed: 6.5 MEDIUM
  56. 2026-09-15 15:22 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-91971?
CVE-2026-91971 is a medium-severity vulnerability; its CVE record was published on September 15, 2026. Vikunja before 2.6.0 fails to apply pixel decode limits to avatar and project-background upload endpoints, allowing authenticated users to upload crafted images that decode to excessive pixel counts. Attackers can upload small images with extreme aspect ratios that consume significant CPU and…
When was CVE-2026-91971 made public?
CVE-2026-91971 was made public on August 31, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on September 15, 2026. EchelonGraph's copy of the record carries a last-modified date of September 21, 2026; the record at its source may have been updated since.
Is CVE-2026-91971 actively exploited?
CVE-2026-91971 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (35th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-91971?
CVE-2026-91971 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-91971?
A fix for CVE-2026-91971 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-91971 are linked in the Vendor Advisories panel on this page.

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