Description
Tor before 0.2.8.9 and 0.2.9.x before 0.2.9.4-alpha had internal functions that were entitled to expect that buf_t data had NUL termination, but the implementation of or/buffers.c did not ensure that NUL termination was present, which allows remote attackers to cause a denial of service (client, hidden service, relay, or authority crash) via crafted data.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | tor | 0.2.8.9-1 | — |
| Debian 13 | tor | 0.2.8.9-1 | — |
| Debian 12 | tor | 0.2.8.9-1 | — |
| Debian 8 | tor | 0.2.5.12-3 | DSA-3694-1 |
| Debian 7 | tor | 0.2.4.27-2 | DLA-663-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | tor | 0.2.4.27-1ubuntu0.1 | — |
Advisories 2
- DSA-3694-1 tor - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-663-1 tor - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- https://blog.torproject.org/blog/tor-0289-released-important-fixes
- https://github.com/torproject/tor/commit/3cea86eb2fbb65949673eb4ba8ebb695c87a57ce
- GLSA-201612-45 vendor-advisory
- [oss-security] 20161019 Re: CVE request for tor mailing-list
- https://trac.torproject.org/projects/tor/ticket/20384
- 95116 vdb-entry
- DSA-3694 vendor-advisory