CVE-2019-20334 — In Netwide Assembler (NASM) 2

In Netwide Assembler (NASM) 2.14.02, stack consumption occurs in expr# functions in asm/eval.c. This potentially affects the relationships among expr0, expr1, expr2, expr3, expr4, expr5, and expr6 (and stdscan in asm/stdscan.c). This is similar to CVE-2019-6290 and CVE-2019-6291.

01What is this vulnerability?

In Netwide Assembler (NASM) 2.14.02, stack consumption occurs in expr# functions in asm/eval.c. This potentially affects the relationships among expr0, expr1, expr2, expr3, expr4, expr5, and expr6 (and stdscan in asm/stdscan.c). This is similar to CVE-2019-6290 and CVE-2019-6291.

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

08Timeline

• Published: 2020-01-04T06:43:42.000Z
• Last modified: 2024-08-05T02:39:09.727Z

09References

• bugzilla.nasm.us — https://bugzilla.nasm.us/show_bug.cgi?id=3392638
• bugzilla.nasm.us — https://bugzilla.nasm.us/show_bug.cgi?id=3392548#c4