CVE-2026-120251
imagecodecs 2026.3.6 through 2026.10.10 Infinite Loop via ccittfax4_decode()
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
imagecodecs 2026.3.6 through 2026.10.10 Infinite Loop via ccittfax4_decode()
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.
- Record
CVE-2026-120251- CVSS 4.0
- 6.8 Medium
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 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-835
- Updated
- 2026-11-06
EUVDEUVD-2026-114748
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.
- Record
EUVD-2026-114748- CVSS 4.0
- 6.8 Medium
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 - Updated
- 2026-11-06
GitHub AdvisoriesGHSA-j736-6c4x-7rx7
imagecodecs 2026.3.6 through 2026.10.10 contains an infinite loop vulnerability in...
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.
- Record
GHSA-j736-6c4x-7rx7- CVSS 4.0
- 6.8 Medium
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-835
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-120251- CVSS 4.0
- 6.8 Medium
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-835
- Updated
- 2026-11-06
OSV
imagecodecs 2026.3.6 through 2026.10.10 Infinite Loop via ccittfax4_decode()
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.
- Record
CVE-2026-120251- CVSS 4.0
- 6.8 Medium
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 - Weakness
- CWE-835
- Updated
- 2026-11-07
OSVopenSUSE-SU-2026:12406-1 No score
python313-imagecodecs-2026.10.10-2.1 on GA media
These are all security issues fixed in the python313-imagecodecs-2026.10.10-2.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:12406-1- Updated
- 2026-11-04
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
python-imagecodecsopenSUSE:Tumbleweed |
before 2026.10.10-2.1 | 2026.10.10-2.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| references | CVE List | |
| affected, aliases, facts, references | OSV | |
| facts | NVD, OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-120251 is a medium vulnerability (CVSS 6.8) in Cgohlke Imagecodecs, published November 1, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.12%, the 2nd percentile. Fixed in python-imagecodecs 2026.10.10-2.1.
References
github.com/cgohlke/imagecodecs/issues/158
vulncheck.com/advisories/imagecodecs-2026.3.6-through-2026.10.10-infinite-loop-via-ccittfax4-decode
nvd.nist.gov/vuln/detail/CVE-2026-120251
suse.com/security/cve/CVE-2026-120251