Bug 2564500 (CVE-2026-120251)

Summary: CVE-2026-120251 imagecodecs: imagecodecs: Denial of Service via infinite loop in CCITT Group 4 decoding
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in imagecodecs. This vulnerability allows an attacker to cause a Denial of Service (DoS) by tricking a user or application into processing a specially crafted CCITT Group 4 fax image stream. An infinite loop in the fax decoding routine causes the process to consume excessive CPU resources and hang indefinitely until terminated.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2565166, 2565168, 2565169    
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Description OSIDB Bzimport 2026-11-01 01:02:25 UTC
imagecodecs 2026.3.6 through 2026.10.10 contains an infinite loop vulnerability in ccitt_fax4_decode_size() that allows attackers to hang the calling process by supplying a crafted CCITT Group 4 stream. Attackers can provide an 8-byte G4 stream lacking EOFB to ccittfax4_decode() or the numcodecs Ccittfax4 codec, consuming full CPU until the process is killed.