CVE-2026-22184: zlib · Out-of-bounds Write
Affects zlibSource CVE Database V5
Not known to be exploited · CVSS 4.6 Medium.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 7 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| zlib softwarezlib | Affected
| Fixed in– |
GitHubmadler/zlibpkg:github/madler/zlibOther threats | Affected
| Fixed in– |
GitHubzlibpkg:github/zlibOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Since the vulnerability affects only the untgz standalone utility and not the core zlib library, users who do not use this utility are not impacted. For those using untgz, avoid processing archives with excessively long names or consider disabling use of the untgz utility until a fix is available. Monitor the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-22184 for updates on patches or official fixes.
Description
zlib versions up to and including 1.3.1.2 include a global buffer overflow in the untgz utility located under contrib/untgz. The vulnerability is limited to the standalone demonstration utility and does not affect the core zlib compression library. The flaw occurs when a user executes the untgz command with an excessively long archive name supplied via the command line, leading to an out-of-bounds write in a fixed-size global buffer.
References
- seclists.org/fulldisclosure/2026/Jan/3 (opens in a new tab)
- zlib.net (opens in a new tab)
- github.com/madler/zlib (opens in a new tab)
- vulncheck.com/advisories/zlib-untgz-global-buffer-overflow-in-tgzfname (opens in a new tab)
- github.com/madler/zlib/issues/1142 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-22184 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2427688 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-22184.json (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-470355.html (opens in a new tab)