SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

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.

CRITICAL 9.3EPSS 0.20%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.20%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 3.1
9.3 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H
EPSS
0.20% probability · 10th percentile
CISA KEV
Not listed
Weakness
CWE-787
Affected
torproject/tor
Source
cve@mitre.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.