Tor OOB Write in Consensus parsing before 0.4.9.9
CVE-2026-77642 Published on August 20, 2026
tor before 0.4.9.9 was prone to an out-of-bounds write when parsing a consensus or detached signature with unexpected signature digest type. Impact is minor for most Tor roles, but potentially major for directory authorities. This is TROVE-2026-019.
Vulnerability Analysis
CVE-2026-77642 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and a high impact on availability.
Weakness Type
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-77642 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-77642
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Affected Versions
torproject Tor:- Version 0.2.8.2-alpha and below 0.4.9.9 is affected.