CVE-2023-49558 — An issue in YASM 1

An issue in YASM 1.3.0.86.g9def allows a remote attacker to cause a denial of service via the expand_mmac_params function in the modules/preprocs/nasm/nasm-pp.c component.

01What is this vulnerability?

An issue in YASM 1.3.0.86.g9def allows a remote attacker to cause a denial of service via the expand_mmac_params function in the modules/preprocs/nasm/nasm-pp.c component.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2024-01-02T00:00:00.000Z
• Last modified: 2025-06-03T14:47:08.846Z

09References

• github.com — https://github.com/yasm/yasm/issues/252