CVE-2020-21686
CVE-2020-21686 is a medium-severity vulnerability in Nasm Netwide Assembler with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-562.
Key facts
- Severity: Medium (CVSS 3.x base score 5.5)
- EPSS exploit prediction: 0% (30th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-562
- Affected product: Nasm Netwide Assembler
- Published:
- Last modified:
Description
A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.
Frequently asked questions
- What is CVE-2020-21686?
- A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.
- How severe is CVE-2020-21686?
- CVE-2020-21686 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2020-21686 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-21686?
- CVE-2020-21686 affects Nasm Netwide Assembler. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2020-21686?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2020-21686 published?
- CVE-2020-21686 was published on 2023-08-22 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:nasm:netwide_assembler:*:*:*:*:*:*:*:*
More vulnerabilities in Nasm Netwide Assembler
- CVE-2004-1287 — Critical (CVSS 10.0): Buffer overflow in the error function in preproc.c for NASM 0.98.38 1.2 allows attackers to execute arbitrary code via…
- CVE-2020-24978 — Critical (CVSS 9.8): In NASM 2.15.04rc3, there is a double-free vulnerability in pp_tokline asm/preproc.c. This is fixed in commit…
- CVE-2026-6068 — Critical (CVSS 9.6): NASM contains a heap use after free vulnerability in response file (-@) processing where a dangling pointer to freed…
- CVE-2008-7177 — Critical (CVSS 9.3): Buffer overflow in the listing module in Netwide Assembler (NASM) before 2.03.01 has unknown impact and attack vectors,…
- CVE-2023-31722 — High (CVSS 7.8): There exists a heap buffer overflow in nasm 2.16.02rc1 (GitHub commit: b952891).
- CVE-2022-44370 — High (CVSS 7.8): NASM v2.16 was discovered to contain a heap buffer overflow in the component quote_for_pmake() asm/nasm.c:856
All CVEs affecting Nasm Netwide Assembler →
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