Out-of-bounds write in torproject Tor
Priority MEDIUM 40CWE-787Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00353 29th percentileScored 2026-11-07
Fix Fixed Tor (torproject): 0.4.9.9
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| torproject | Tor | 0.2.8.2-alpha to before 0.4.9.9 | 0.4.9.9 | Patch available | CNA |
- Tor Vendortorproject Affected 0.2.8.2-alpha to before 0.4.9.9 Fixed in 0.4.9.9 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:* | before 0.4.9.9 | Vulnerable | torproject |
- cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:* Versions before 0.4.9.9 Vulnerable ·torproject
Remediation
- Fix · CNA Tor (torproject) Fixed in 0.4.9.9
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
torproject Tor 0.4.9.9
4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2026-54111 tor before 0.4.9.9 was prone to a NULL write after free when sending a CONFLUX_SWITCH…Priority LOW 36
- TI-2026-54109 Tor before 0.4.9.9 was prone to a compression bomb bypass where an attacker could…Priority LOW 30
- TI-2026-54110 tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip…Priority LOW 24
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-77642
- 2026-10-03 Alias added: GHSA-36cc-rhpv-jrxc
References
More torproject Tor vulnerabilities
- TI-2016-07433 Use after free in Mozilla Firefox KEVCVSS 3.1HIGH 7.5
- TI-2023-09419 The SafeSocks option in Tor before 0.4.7.13 has a logic error in which the unsafe SOCKS4… CVSS 3.1MEDIUM 6.5
- TI-2018-00448 Use after free in Tor CVSS 3.0HIGH 7.5
- TI-2026-54108 Race condition in torproject Tor CVSS 3.1CRITICAL 9.0
- TI-2026-32508 Tor before 0.4.9.7 has an out-of-bounds read when an END, a TRUNCATE, or a TRUNCATED cell… CVSS 3.1CRITICAL 9.1
- TI-2019-06464 In Tor before 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x before 0.3.5.8, and 0.4.x before… CVSS 3.0HIGH 7.5
Sources
- CVE-2026-77642 · CVE Program
- CVE-2026-77642 · NVD
- FIRST EPSS
- GHSA-36cc-rhpv-jrxc · GitHub Advisory Database · CC BY 4.0
- CVE-2026-77642 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences