CVE-2026-25156
HotCRP vulnerable to stored XSS via comment attachments
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
HotCRP is conference review software. HotCRP versions from October 2025 through January 2026 delivered documents of all types with inline Content-Disposition, causing them to be rendered in the user’s browser rather than downloaded. (The intended behavior was for only `text/plain`, `application/pdf`, `image/gif`, `image/jpeg`, and `image/png` to be delivered inline, though adding `save=0` to the document URL could request inline delivery for any document.) This made users who clicked a document link vulnerable to cross-site scripting attacks. An uploaded HTML or SVG document would run in the viewer’s browser with access to their HotCRP credentials, and Javascript in that document could eventually make arbitrary calls to HotCRP’s API. Malicious documents could be uploaded to submission fields with “file upload” or “attachment” type, or as attachments to comments. PDF upload fields were not vulnerable. A search of documents uploaded to hotcrp.com found no evidence of exploitation. The vulnerability was introduced in commit aa20ef288828b04550950cf67c831af8a525f508 (11 October 2025), present in development versions and v3.2, and fixed in commit 8933e86c9f384b356dc4c6e9e2814dee1074b323 and v3.2.1. Additionally, c3d88a7e18d52119c65df31c2cc994edd2beccc5 and v3.2.1 remove support for `save=0`.
Timeline
ID reserved
By GitHub_M
- 1 day later
· 1 day later
Published
- 3 days later
· 3 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N |
| NVDNVD · Analyzed | 3.1 | Medium6.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.28% · top 80% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.3.
Weakness
Affected products
References (4)
- https://github.com/kohler/hotcrp/security/advisories/GHSA-p88p-2f2p-2476 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/kohler/hotcrp/commit/8933e86c9f384b356dc4c6e9e2814dee1074b323 (opens in a new tab)x_refsource_MISC
- https://github.com/kohler/hotcrp/commit/aa20ef288828b04550950cf67c831af8a525f508 (opens in a new tab)x_refsource_MISC
- https://github.com/kohler/hotcrp/commit/c3d88a7e18d52119c65df31c2cc994edd2beccc5 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-25156)Record last updated .