CVE-2026-22184
zlib versions up to and including 1.3.1.2 include a global buffer overflow in the untgz utility located under contrib/untgz.
Does this matter?
Lower severity and a low EPSS score (0.42%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 4.6 MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.42% probability · 36th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787, CWE-120
- Affected
- zlib/zlib
- Source
- disclosure@vulncheck.com
References
- https://github.com/madler/zlibProduct
- https://seclists.org/fulldisclosure/2026/Jan/3Mailing List, Third Party Advisory
- https://www.vulncheck.com/advisories/zlib-untgz-global-buffer-overflow-in-tgzfnameThird Party Advisory
- https://zlib.net/Product
- https://github.com/madler/zlib/issues/1142Issue Tracking
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.