| Name | CVE-2019-12521 |
| Description | An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-2278-1, DSA-4682-1, ELA-271-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| squid (PTS) | buster (security), buster, buster (lts) | 4.6-1+deb10u10 | fixed |
| bullseye (security), bullseye | 4.13-10+deb11u3 | fixed | |
| bookworm (security), bookworm | 5.7-2+deb12u2 | fixed | |
| sid, trixie | 6.12-1 | fixed | |
| squid3 (PTS) | jessie, jessie (lts) | 3.5.23-5+deb8u7 | fixed |
| stretch (security) | 3.5.23-5+deb9u7 | fixed | |
| stretch (lts), stretch | 3.5.23-5+deb9u10 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| squid | source | wheezy | (unfixed) | end-of-life | ||
| squid | source | buster | 4.6-1+deb10u2 | DSA-4682-1 | ||
| squid | source | (unstable) | 4.11-1 | |||
| squid3 | source | wheezy | (unfixed) | end-of-life | ||
| squid3 | source | jessie | 3.5.23-5+deb8u1 | ELA-271-1 | ||
| squid3 | source | stretch | 3.5.23-5+deb9u2 | DLA-2278-1 | ||
| squid3 | source | (unstable) | (unfixed) |
http://www.squid-cache.org/Advisories/SQUID-2019_12.txt
Squid 4: http://www.squid-cache.org/Versions/v4/changesets/squid-4-fdd4123629320aa1ee4c3481bb392437c90d188d.patch