Description
lib/rfc1035.c in Squid 2.x, 3.0 through 3.0.STABLE22, and 3.1 through 3.1.0.15 allows remote attackers to cause a denial of service (assertion failure) via a crafted DNS packet that only contains a header.
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 | squid | 2.7.STABLE8-1 | — |
| Debian 13 | squid | 2.7.STABLE8-1 | — |
| Debian 12 | squid | 2.7.STABLE8-1 | — |
| Debian 5.0 | squid | 2.7.STABLE3-4.1lenny1 | DSA-1991-1 |
| Debian 5.0 | squid3 | 3.0.STABLE8-3+lenny3 | DSA-1991-1 |
| Debian 4.0 | squid | 2.6.5-6etch5 | DSA-1991-1 |
| Debian 4.0 | squid3 | 3.0.PRE5-5+etch2 | DSA-1991-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | squid | 7:2.6.STABLE21-6.el5 | RHSA-2010:0221 |
Advisories 2
- RHSA-2010:0221 Red Hat Security Advisory: squid security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-1991-1 squid squid3 - denial of service Debian Security (DSA / DLA) · Mar 9, 2026
References
- 38451 third-party-advisory
- 38455 third-party-advisory
- 62044 vdb-entry
- 37522 vdb-entry
- http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-9853.patch
- http://www.squid-cache.org/Versions/v2/HEAD/changesets/12597.patch
- squid-dns-dos(56001) vdb-entry
- http://events.ccc.de/congress/2009/Fahrplan/attachments/1483_26c3_ipv4_fuckups.pdf
- http://www.squid-cache.org/Advisories/SQUID-2010_1.txt
- oval:org.mitre.oval:def:11270 vdb-entry signature
- http://www.squid-cache.org/Versions/v3/3.0/changesets/squid-3.0-9163.patch
- 1023520 vdb-entry
- ADV-2010-0260 vdb-entry