Buffer overflow in Torproject Tor

CVE-2026-77642

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 class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-77642?
CVE-2026-77642 is a high-severity vulnerability in Torproject Tor, classified under Out-of-bounds Write. CVSS score: 7.5/10. Published 2026-08-20.
How severe is CVE-2026-77642?
High severity. CVSS v3 base score is 7.5 out of 10.