CVE-2026-91939 json
Cotonti 1.0.0 Comments Plugin PHP Object Injection via ci Parameter
published last mo. modified last mo. also EUVD-2026-80000
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 62%
- public exploits
- 0
- none known
Summary
Cotonti 1.0.0 Comments plugin passes the ci GET parameter to unserialize() without allowed_classes restriction, allowing unauthenticated attackers to instantiate arbitrary PHP classes with attacker-controlled properties. Attackers can exploit PHP object injection through crafted serialized payloads to trigger gadget chains and achieve database manipulation or code execution.
Patch / fix
- github.com/Cotonti/Cotonti#1889 pull request
Is CVE-2026-91939 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- total
- Assessed
- last mo.
Exploit prediction
0.98% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-11).
Exploits and checks
- github.com https://github.com/Cotonti/Cotonti/issues/1888 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- Cotonti Cotonti
Classification
- Weakness
-
- CWE-502 Deserialization of Untrusted Data
References
-
github.com
/Cotonti/Cotonti/pull/1889
patch, issue-tracking
-
github.com
/Cotonti/Cotonti/issues/1888
issue-tracking, exploit
-
github.com
/Cotonti/Cotonti/blob/1.0.0/plugins/comments/inc/CommentsWidget.php
technical-description
-
github.com
/Cotonti/Cotonti/blob/1.0.0/plugins/comments/controllers/actions/DisplayAction.php
technical-description
-
github.com
/Cotonti/Cotonti/blob/1.0.0/plugins/comments/comments.setup.php
technical-description
-
github.com
/Cotonti/Cotonti
product
-
vulncheck.com
/advisories/cotonti-1.0.0-comments-plugin-php-object-injection-via-ci-parameter
third-party-advisory
Sources
- CVE List CVE-2026-91939
- NVD CVE-2026-91939
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.