CVE-2026-120251: cgohlke imagecodecs · Infinite Loop
Affects cgohlke imagecodecsSource CVE Database V5
Not known to be exploited · CVSS 6.8 Medium.
Data as of 1 Nov 2026, 01:21 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.8 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 5.5 |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 1 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 31 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| cgohlkeimagecodecs | Affected
| Fixed in– |
PyPIimagecodecspkg:pypi/imagecodecsOther 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
Until a fix is available, avoid processing untrusted CCITT Group 4 streams with the affected versions of imagecodecs to prevent denial of service.
Description
imagecodecs versions 2026.3.6 through 2026.10.10 contain an infinite loop vulnerability in the ccitt_fax4_decode_size() function. This flaw allows an attacker to hang the calling process by providing a crafted CCITT Group 4 stream that lacks an End Of Facsimile Block (EOFB). The vulnerability results in full CPU consumption until the affected process is terminated.
References
- github.com/cgohlke/imagecodecs/issues/158 (opens in a new tab)
- github.com/cgohlke/imagecodecs/blob/v2026.10.10/3rdparty/ccitt/ccitt.c (opens in a new tab)
- github.com/cgohlke/imagecodecs (opens in a new tab)
- vulncheck.com/advisories/imagecodecs-2026.3.6-through-2026.10.10-infinite-loop-via-ccittfax4-decode (opens in a new tab)