CVE-2026-120251 PUBLISHED

imagecodecs 2026.3.6 through 2026.10.10 Infinite Loop via ccittfax4_decode()

Assigner: VulnCheck
Reserved: 31.10.2026 Published: 01.11.2026 Updated: 01.11.2026

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.

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 6.8

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Local	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS Score: 5.5

Attack Vector	Local	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	Required	Availability Impact	High

CVSS 3.1

Product Status

Vendor	cgohlke
Product	imagecodecs
Versions	Default: unaffected affected from 2026.3.6 to 2026.10.10 (incl.)

CVE-2026-120251 PUBLISHED

imagecodecs 2026.3.6 through 2026.10.10 Infinite Loop via ccittfax4_decode()

Metrics

Product Status

Credits

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Problem Types