CVE-2023-22485

cmark-gfm out-of-bounds read in validate_protocol

MEDIUM
5.3
CVSS Score
Published: January 24, 2023 at 12:26 AM UTC
Updated: June 17, 2026 at 05:35 AM UTC
1 product affected across 1 vendorCmark Gfm

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. In versions prior 0.29.0.gfm.7, a crafted markdown document can trigger an out-of-bounds read in the `validate_protocol` function. We believe this bug is harmless in practice, because the out-of-bounds read accesses `malloc` metadata without causing any visible damage.This vulnerability has been patched in 0.29.0.gfm.7.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Cmark Gfm· GitHubgithub-action
95%
v < 0.29.0.gfm.7
Affected range stops below 0.29.0.gfm.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-125CWE-91

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