CVE-2026-91857

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Affected versions of MISP expose several state-changing controller actions without restricting them to POST.

The affected actions are:

  • EventReportsController::purgeUnusedPictures()
  • NoticelistsController::enableNoticelist()
  • ServersController::removeOrphanedCorrelations()
  • WorkflowsController::rebuildRedis()

The patch adds allowMethod(['post']) to each action, preventing them from being triggered through ordinary GET requests.

For purgeUnusedPictures(), the corresponding UI previously used $.get(). The fix converts that request to POST and supplies X-CSRF-Token, while the controller enables header-only CSRF validation for that AJAX action.

Because GET requests can be induced cross-origin through links, images, redirects, or navigation, accepting GET for these state-changing operations can let an attacker trigger them using the authenticated victim's session.

Version affected: ≤2.5.45

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
24(Track)
EG Risk 24/100SSVC: Track

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
Severity53% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 16, 2026

Advisory Details (1)

Auto-updated Sep 15, 2026
Patch available. Sources: github_commit.
github_commit Patch Available

commit b4a5486b5 (MISP/MISP)

Patch available: MISP/MISP v2.5.46 (contains commit b4a5486b5)

https://github.com/MISP/MISP/commit/b4a5486b5

Vendor Advisories for CVE-2026-91857(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 22× in last 7d / 37× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-09-24 21:41 UTCEG score recompute
  2. 2026-09-24 21:41 UTCGHSA enrichment
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-23 23:26 UTCEG score recompute
  5. 2026-09-23 23:26 UTCGHSA enrichment
  6. 2026-09-23 17:54 UTCEPSS rescore
  7. 2026-09-23 01:16 UTCEG score recompute
  8. 2026-09-23 01:16 UTCGHSA enrichment
  9. 2026-09-22 16:01 UTCEPSS rescore
  10. 2026-09-22 03:06 UTCEG score recompute
  11. 2026-09-22 03:06 UTCGHSA enrichment
  12. 2026-09-21 21:09 UTCEPSS rescore
  13. 2026-09-21 04:55 UTCEG score recompute
  14. 2026-09-21 04:55 UTCGHSA enrichment
  15. 2026-09-20 20:16 UTCEPSS rescore
  16. 2026-09-20 06:28 UTCEG score recompute
  17. 2026-09-20 06:27 UTCGHSA enrichment
  18. 2026-09-19 08:13 UTCEG score recompute
  19. 2026-09-19 08:13 UTCGHSA enrichment
  20. 2026-09-18 19:28 UTCEPSS rescore
  21. 2026-09-18 10:04 UTCEG score recompute
  22. 2026-09-18 10:04 UTCGHSA enrichment
  23. 2026-09-17 19:32 UTCEPSS rescore
  24. 2026-09-17 11:54 UTCEG score recompute
  25. 2026-09-17 11:54 UTCGHSA enrichment
Show 12 more
  1. 2026-09-16 14:09 UTCEPSS rescore
  2. 2026-09-16 13:44 UTCGHSA enrichment
  3. 2026-09-16 12:41 UTCEG score recompute
  4. 2026-09-16 12:41 UTCGHSA enrichment
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 14:32 UTCEG score recompute
  7. 2026-09-15 14:32 UTCGHSA enrichment
  8. 2026-09-15 13:33 UTCEG score recompute
  9. 2026-09-15 13:33 UTCGHSA enrichment
  10. 2026-09-15 10:28 UTCEG score recompute
  11. 2026-09-15 09:28 UTCEG score recompute
  12. 2026-09-15 09:27 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-91857?
CVE-2026-91857 is a medium vulnerability published on September 15, 2026. Affected versions of MISP expose several state-changing controller actions without restricting them to POST. The affected actions are: EventReportsController::purgeUnusedPictures() NoticelistsController::enableNoticelist() ServersController::removeOrphanedCorrelations()…
When was CVE-2026-91857 disclosed?
CVE-2026-91857 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91857 actively exploited?
CVE-2026-91857 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 89.6% of all scored CVEs.
What is the CVSS score of CVE-2026-91857?
CVE-2026-91857 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-91857?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-91857, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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