CVE-2026-77401Zope AccessControl: Information disclosure through Python string `format` and `format_map` functions
- 6.8MediumCVSS base score
- 0.47%Exploitation in 30 daysEPSS · top 59% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Zope AccessControl provides a general security framework for use in Zope. Prior to 7.4, applications that allow untrusted users to create and execute AccessControl-controlled Python code do not safely guard str.format and str.format_map when those methods are reached through a str subclass. In both ImplPython.py and cAccessControl.c, Python formatting can recursively access attributes and subscriptions using unrestricted getattr and getitem behavior instead of the policy-restricted getattr and getitem operations. A controlled format string can therefore disclose objects reachable from values available to the formatting operation. This issue is fixed in version 7.4.
Timeline
ID reserved
By GitHub_M
- 27 days later
· 27 days later
Published
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 | Medium6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
| NVDNVD · Awaiting Analysis | 3.1 | Medium6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.47% · top 59% of all CVEs (14 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: Medium 6.8.
Affected products
zopefoundation · AccessControl
- affected < 7.4
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIAccessControlGHSA-pq59-9fq7-m886 (opens in a new tab)
References
References3
- https://github.com/zopefoundation/AccessControl/security/advisories/GHSA-pq59-9fq7-m886 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/zopefoundation/AccessControl/commit/f980450eea416718be62847f34dfd51822938e43 (opens in a new tab)x_refsource_MISC
- https://github.com/zopefoundation/AccessControl/releases/tag/7.4 (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)
- EUVD EUVD-2026-80790 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-pq59-9fq7-m886 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-77401)Record last updated .