CVE-2026-91984

MEDIUMPre-NVD 4.34.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (18th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-78655 (ENISA EUVD) · GHSA-ccgq-fx7h-2v4c (GitHub Security Advisories) · GHSA-w39f-h553-h2mx (GitHub Security Advisories) · GO-2026-6755 (OSV.dev)Source: ENISA EUVD

4.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 4.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Vikunja before 2.6.0 fails to validate that user-supplied project_view_id in task-position requests belongs to the task's project. Authenticated attackers can insert task position rows into arbitrary other tenant project views via POST or PUT task-position endpoints.

CVSS v3
4.3
EG Score
4.3MEDIUMmedium confidence
EG Risk
19
EG Risk 19/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity43% × 45%
Impact severity (EG Severity): CVSS 4.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (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
0.3%
EPSS %ILE
18th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (4.3): severity, escalated by confirmed exploitation. This CVE's 4.3 is its impact severity (EG Severity), not escalated.

EG Severity
4.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-11). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

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

Exploitation none (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.

The score's inputs: 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 17, 2026

Advisory Details (2)

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

Vikunja before 2.6.0 Broken Object-Level Authorization via task-position | Advisories | VulnCheck

https://www.vulncheck.com/advisories/vikunja-before-2.6.0-broken-object-level-authorization-via-task-position
GitHub advisoryMentions a patch (unverified)

Cross-tenant task-position rows can be injected into arbitrary project views via the unvalidated project_view_id in the task position endpoint (v1 and v2) · Advisory · go-vikunja/vikunja · GitHub

https://github.com/go-vikunja/vikunja/security/advisories/GHSA-w39f-h553-h2mx

Vendor Advisories for CVE-2026-91984(1)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
gocode.vikunja.io/api @ 2.6.0 (fixes <= 2.5.0)—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

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
  • every version on: no fix on record
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 33× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 117 rows on record for this CVE.

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. None are among the latest 100 rows. The 17 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:58 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  2. 2026-11-12 16:35 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  3. 2026-11-12 09:38 UTCEchelonGraph re-scored
  4. 2026-11-12 09:37 UTCGHSA enrichmentGHSA-w39f-h553-h2mx · GitHub severity MODERATE
  5. 2026-11-11 16:41 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  6. 2026-11-10 16:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  7. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  8. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  9. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  10. 2026-11-06 16:40 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  11. 2026-11-05 16:39 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  12. 2026-11-04 16:37 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  13. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  14. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  15. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  16. 2026-11-01 07:37 UTCGHSA enrichmentGHSA-w39f-h553-h2mx · GitHub severity MODERATE
  17. 2026-11-01 07:37 UTCEchelonGraph re-scored
  18. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  19. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  20. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  21. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  22. 2026-10-27 18:25 UTCOSV refresh
  23. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  24. 2026-10-26 16:33 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  25. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.3% · 18th percentile
Show 75 more
  1. 2026-10-25 13:50 UTCEchelonGraph re-scored
  2. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  3. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  4. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  5. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  6. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  7. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  8. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  9. 2026-10-18 03:00 UTCEchelonGraph re-scored
  10. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  11. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  12. 2026-10-15 18:37 UTCEchelonGraph re-scored
  13. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  14. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  15. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  17. 2026-10-12 14:45 UTCEchelonGraph re-scored
  18. 2026-10-11 19:13 UTCEchelonGraph re-scored
  19. 2026-10-11 16:29 UTCEchelonGraph re-scored
  20. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  21. 2026-10-11 13:44 UTCEchelonGraph re-scored
  22. 2026-10-11 05:40 UTCEchelonGraph re-scored
  23. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  24. 2026-10-09 23:38 UTCEchelonGraph re-scored
  25. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  26. 2026-10-08 22:38 UTCEchelonGraph re-scored
  27. 2026-10-08 22:38 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  28. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  29. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  30. 2026-10-07 15:18 UTCEchelonGraph re-scored
  31. 2026-10-07 15:18 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  32. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  33. 2026-10-06 14:20 UTCEchelonGraph re-scored
  34. 2026-10-06 14:19 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  35. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  36. 2026-10-05 13:21 UTCEchelonGraph re-scored
  37. 2026-10-05 13:21 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  38. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  39. 2026-10-04 12:04 UTCEchelonGraph re-scored
  40. 2026-10-04 12:04 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  41. 2026-10-03 11:06 UTCEchelonGraph re-scored
  42. 2026-10-03 11:06 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  43. 2026-10-02 10:08 UTCEchelonGraph re-scored
  44. 2026-10-02 10:08 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  45. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  46. 2026-10-01 09:10 UTCEchelonGraph re-scored
  47. 2026-10-01 09:10 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  48. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  49. 2026-09-30 08:13 UTCEchelonGraph re-scored
  50. 2026-09-30 08:13 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  51. 2026-09-29 07:15 UTCEchelonGraph re-scored
  52. 2026-09-29 07:15 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  53. 2026-09-28 06:10 UTCEchelonGraph re-scored
  54. 2026-09-28 06:10 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  55. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  56. 2026-09-27 05:13 UTCEchelonGraph re-scored
  57. 2026-09-27 05:13 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  58. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  59. 2026-09-26 04:15 UTCEchelonGraph re-scored
  60. 2026-09-26 04:15 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  61. 2026-09-25 03:15 UTCEchelonGraph re-scored
  62. 2026-09-25 03:15 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  63. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  64. 2026-09-24 02:16 UTCEchelonGraph re-scored
  65. 2026-09-24 02:16 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  66. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  67. 2026-09-23 01:19 UTCEchelonGraph re-scored
  68. 2026-09-23 01:19 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  69. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  70. 2026-09-22 00:21 UTCEchelonGraph re-scored
  71. 2026-09-22 00:21 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  72. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  73. 2026-09-20 23:23 UTCEchelonGraph re-scored
  74. 2026-09-20 23:23 UTCGHSA enrichmentGHSA-ccgq-fx7h-2v4c · GitHub CVSS 4.3
  75. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 11th percentile

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Frequently asked(5)

What is CVE-2026-91984?
CVE-2026-91984 is a medium-severity vulnerability; its CVE record was published on September 15, 2026. Vikunja before 2.6.0 fails to validate that user-supplied project_view_id in task-position requests belongs to the task's project. Authenticated attackers can insert task position rows into arbitrary other tenant project views via POST or PUT task-position endpoints.
When was CVE-2026-91984 made public?
CVE-2026-91984 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 17, 2026; the record at its source may have been updated since.
Is CVE-2026-91984 actively exploited?
CVE-2026-91984 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (18th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-91984?
CVE-2026-91984 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-91984?
A fix for CVE-2026-91984 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-91984 are linked in the Vendor Advisories panel on this page.

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