CVE-2023-37463 | Quadratic complexity bugs may lead to a denial of service

Exp

cmark-gfm is an extended version of the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. Three polynomial time complexity issues in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. These vulnerabilities have been patched in 0.29.0.gfm.12.

Published: 2023-07-13 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-37463 is rated Exploit Available (56/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.59%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-37463

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-37463

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.35% 0.59% +0.24%
2 2026-06-12 0.21% 0.35% +0.15%
3 2026-04-19 — 0.21% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-37463

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 4.7 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-37463

OS Trackers for CVE-2023-37463

vendor priority summary link
debian not yet assigned CVE-2023-37463 not yet assigned priority: Debian including 4 source packages (cmark-gfm, python-cmarkgfm, r-cran-commonmark, ruby-commonmarker), 20 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 12, open 8. https://security-tracker.debian.org/tracker/CVE-2023-37463
suse medium CVE-2023-37463 severity moderate: SUSE including 8 source package names (cmark, cmark-devel, …), 12 product×package rows across 7 product lines (SUSE Linux Enterprise Module for Development Tools 15 SP4, SUSE Linux Enterprise Module for Development Tools 15 SP5, … (7 product lines)): Known Not Affected 7, Fixed 5. https://www.suse.com/security/cve/CVE-2023-37463/
ubuntu medium CVE-2023-37463 medium priority: Ubuntu including 1 source packages (cmark-gfm), 11 status rows across 11 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, trusty, upstream, xenial): ignored 6, not-affected 4, released 1. https://ubuntu.com/security/CVE-2023-37463

Affected software / configurations for CVE-2023-37463

Vendor Product Version Raw CPE
github cmark-gfm < 0.29.0.gfm.12 cpe:2.3:a:github:cmark-gfm:*:*:*:*:*:*:*:*

References for CVE-2023-37463

cvelogic Threat Intelligence