CVE-2026-77642
CVE-2026-77642 is a high-severity vulnerability in Torproject Tor with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 0% (27th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Torproject Tor
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-77642?
- CVE-2026-77642 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.
- Is CVE-2026-77642 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-77642?
- CVE-2026-77642 affects Torproject Tor. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-77642?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-77642 published?
- CVE-2026-77642 was published on 2026-08-20 and last updated on 2026-09-08.
References
Affected products (1)
- cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
More vulnerabilities in Torproject Tor
- CVE-2026-77638 — High (CVSS 8.9): Tor before 0.4.9.11 is prone to a race condition where in just the right circumstances a rendezvous point could…
- CVE-2022-33903 — High (CVSS 7.5): Tor 0.4.7.x before 0.4.7.8 allows a denial of service via the wedging of RTT estimation.
- CVE-2021-38385 — High (CVSS 7.5): Tor before 0.3.5.16, 0.4.5.10, and 0.4.6.7 mishandles the relationship between batch-signature verification and…
- CVE-2021-34550 — High (CVSS 7.5): An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-006. The v3 onion service descriptor parsing allows…
- CVE-2021-34549 — High (CVSS 7.5): An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-005. Hashing is mishandled for certain retrieval of…
- CVE-2021-34548 — High (CVSS 7.5): An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-003. An attacker can forge RELAY_END or RELAY_RESOLVED to…
All CVEs affecting Torproject Tor →
Other CWE-787 (Out-of-bounds Write) vulnerabilities
- CVE-2026-42369 — Critical (CVSS 10.0): GV-VMS V20 is a Video Monitoring Software used to gather the feeds of many surveillance cameras and manage other…
- CVE-2026-4746 — Critical (CVSS 10.0): Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src modules). This vulnerability is…
- CVE-2025-43300 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 15.8.5 and iPadOS…
- CVE-2025-24201 — Critical (CVSS 10.0): An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in…
- CVE-2024-42479 — Critical (CVSS 10.0): llama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause…
- CVE-2024-39791 — Critical (CVSS 10.0): Stack-based buffer overflow vulnerabilities affecting Vonets industrial wifi bridge relays and wifi bridge…