CVE-2026-22184: zlib <= 1.3.1.2 untgz Global Buffer Overflow in TGZfname()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-07 · updated 2026-09-01
Weakness: CWE-787

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.

Affected products

zlib: through 1.3.1.2

References

https://github.com/madler/zlib
https://seclists.org/fulldisclosure/2026/Jan/3
https://www.vulncheck.com/advisories/zlib-untgz-global-buffer-overflow-in-tgzfname
https://zlib.net/
https://github.com/madler/zlib/issues/1142
https://access.redhat.com/security/cve/CVE-2026-22184
https://bugzilla.redhat.com/show_bug.cgi?id=2427688
https://cert-portal.siemens.com/productcert/html/ssa-470355.html
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-22184.json

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