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NVD / CVE Program· CNA GitHub_M

CVE-2023-22485: cmark-gfm out-of-bounds read in validate_protocol

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.73% (FIRST EPSS); higher than 54.3% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: github cmark-gfm 0.29.0.gfm.7.

Low priority for now. Upgrade to github cmark-gfm 0.29.0.gfm.7 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Jan 23, 2023
Updated
Jun 17, 2026
EPSS
0.7% · 54th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.3
CNA · GitHub_M
5.3
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
githubcmark-gfm

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • github cmark-gfmbefore 0.29.0.gfm.7

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • github cmark-gfm

    • < 0.29.0.gfm.7affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12cmark-gfmfrom 0—
Debian:12python-cmarkgfmfrom 0—
Debian:12r-cran-commonmarkfrom 0—
Debian:12ruby-commonmarkerfrom 0—
Debian:13cmark-gfmbefore 0.29.0.gfm.13-10.29.0.gfm.13-1
Debian:13python-cmarkgfmbefore 2024.11.20-12024.11.20-1
Debian:13r-cran-commonmarkbefore 1.9.0-11.9.0-1
Debian:13ruby-commonmarkerbefore 0.23.10-10.23.10-1

Same product

github: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-24724Integer overflow in table parsing extension leads to heap memory corruption
    40Plan
  • CVE-2024-22051CommonMarker Integer Overflow Vulnerability
    39Monitor
  • CVE-2023-37463Quadratic complexity bugs may lead to a denial of service
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-22483Jan 23, 2023 · cmark-gfm Quadratic complexity bugs may lead to a denial of service
    30Monitor
  • ← EarlierCVE-2023-22484Jan 23, 2023 · Inefficient Quadratic complexity bug in handle_pointy_brace may lead to a denial of service
    30Monitor
  • Later →CVE-2023-22486Jan 26, 2023 · cmark-gfm Quadratic complexity bug in handle_close_bracket may lead to a denial of service
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
github cmark-gfm0.29.0.gfm.7 · descriptionVendor (CNA)
debian:cmark-gfm0.29.0.gfm.13-1 · Debian:13Package registry (OSV)
debian:python-cmarkgfm2024.11.20-1 · Debian:13Package registry (OSV)
debian:r-cran-commonmark1.9.0-1 · Debian:13Package registry (OSV)
debian:ruby-commonmarker0.23.10-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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