Description
Integer underflow in the unlzw function in unlzw.c in gzip before 1.4 on 64-bit platforms, as used in ncompress and probably others, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted archive that uses LZW compression, leading to an array index error.
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 | gzip | 1.3.12-9 | — |
| Debian 14 | ncompress | 4.2.4.3-1 | — |
| Debian 13 | gzip | 1.3.12-9 | — |
| Debian 13 | ncompress | 4.2.4.3-1 | — |
| Debian 12 | gzip | 1.3.12-9 | — |
| Debian 12 | ncompress | 4.2.4.3-1 | — |
| Debian 5.0 | gzip | 1.3.12-6+lenny1 | DSA-1974-1 |
| Debian 5.0 | ncompress | 4.2.4.2-1+lenny1 | DSA-2074-1 |
| Debian 4.0 | gzip | 1.3.5-15+etch1 | DSA-1974-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | gzip | 1.3.5-11.el5_4.1 | RHSA-2010:0061 |
| RHEL 4 | gzip | 1.3.3-18.el4_8.1 | RHSA-2010:0061 |
| RHEL 3 | gzip | 1.3.3-15.rhel3 | RHSA-2010:0061 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | gzip | 1.8-1.29 | openSUSE-SU-2024:10059-1 |
Advisories 4
- RHSA-2010:0061 Red Hat Security Advisory: gzip security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-2074-1 ncompress - execution of arbitrary code Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1974-1 gzip - arbitrary code execution Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10059-1 gzip-1.8-1.29 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 38220 third-party-advisory
- 40655 third-party-advisory
- http://support.apple.com/kb/HT4435
- ADV-2010-0185 vdb-entry
- http://ncompress.sourceforge.net/#status
- SSRT100018 vendor-advisory
- USN-889-1 vendor-advisory
- oval:org.mitre.oval:def:10546 vdb-entry signature
- 1023490 vdb-entry
- ADV-2010-1872 vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=554418
- http://git.savannah.gnu.org/cgit/gzip.git/commit/?id=a3db5806d012082b9e25cc36d09f19cd736a468f
- APPLE-SA-2010-11-10-1 vendor-advisory
- DSA-1974 vendor-advisory
- MDVSA-2010:020 vendor-advisory
- 40689 third-party-advisory
- 40551 third-party-advisory
- oval:org.mitre.oval:def:7511 vdb-entry signature
- 38223 third-party-advisory
- http://savannah.gnu.org/forum/forum.php?forum_id=6153
- DSA-2074 vendor-advisory
- ADV-2010-1796 vdb-entry
- RHSA-2010:0061 vendor-advisory
- RHSA-2010:0095 vendor-advisory
- MDVSA-2010:019 vendor-advisory
- MDVSA-2011:152 vendor-advisory
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705
- 38225 third-party-advisory
- SUSE-SA:2010:008 vendor-advisory
- 38232 third-party-advisory
- 61869 vdb-entry