CVE-2026-77401 json
Zope AccessControl: Information disclosure through Python string `format` and `format_map` functions
published last mo. modified last mo. also EUVD-2026-80790 , GHSA-pq59-9fq7-m886 , PYSEC-2026-4022
- cvss
- 6.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 41%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi accesscontrol 7.4
- zope accesscontrol 7.4
Is CVE-2026-77401 in your dependencies? 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
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- last mo.
Exploit prediction
0.47% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
| GitHub | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
| OSV | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | accesscontrol | <7.4 |
7.4 |
Affected products
- zopefoundation AccessControl
Classification
- Weakness
-
- CWE-693 Protection Mechanism Failure
References
-
github.com
/zopefoundation/AccessControl/commit/f980450eea416718be62847f34dfd51822938e43
web
-
github.com
/zopefoundation/AccessControl/security/advisories/GHSA-pq59-9fq7-m886
web
-
github.com
/zopefoundation/AccessControl/releases/tag/7.4
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-77401
advisory
-
github.com
/zopefoundation/AccessControl
package
-
pypi.org
/project/accesscontrol
package
-
github.com
/advisories/GHSA-pq59-9fq7-m886
advisory
Sources
- CVE List CVE-2026-77401
- GitHub Advisory GHSA-pq59-9fq7-m886
- NVD CVE-2026-77401
- OSV PYSEC-2026-4022
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.