CVE-2026-77642: CWE-787 Out-of-bounds Write in torproject Tor
Description
CVE-2026-77642 is an out-of-bounds write vulnerability in Tor versions before 0.4.9.9. It occurs when parsing a consensus or detached signature with an unexpected signature digest type. The impact is generally minor for most Tor roles but can be significant for directory authorities. This vulnerability has a CVSS score of 7.5, indicating high severity.
CVSS v3.1
Score 7.5high
Affected software
torproject
Tor
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Tor versions prior to 0.4.9.9 contain a CWE-787 out-of-bounds write vulnerability triggered by parsing consensus or detached signatures that include an unexpected signature digest type. This flaw can cause memory corruption, potentially impacting the stability and security of directory authorities more severely than other Tor roles. The vulnerability is tracked as TROVE-2026-019 and CVE-2026-77642.
Potential Impact
The vulnerability can lead to an out-of-bounds write, which may cause denial of service or other memory corruption issues. While the impact is minor for most Tor roles, directory authorities could experience major impact due to this flaw. There is no indication of confidentiality or integrity loss, but availability impact is high for affected roles.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch link is provided at this time. Users and administrators should monitor torproject advisories for updates and apply patches once available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-08-20T21:15:49.322Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a8773a6acd9273b49283122
Added to database: 08/20/2026, 21:37:42 UTC
Last enriched: 09/10/2026, 13:33:34 UTC
Last updated: 10/05/2026, 06:48:18 UTC
Views: 80
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