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Fencer Vulns
medium 5.5

CVE-2021-45257 json

An infinite loop vulnerability exists in nasm 2.16rc0 via the gpaste_tokens function.

published 2021-12-22 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-32037

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

An infinite loop vulnerability exists in nasm 2.16rc0 via the gpaste_tokens function.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-45257 updated cvss 3.3

nasm: Infinite loop via the paste_tokens function

  • Red Hat Enterprise Linux 8 nasm Red Hat Enterprise Linux 9 nasm
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 nasm, nasm-rdoff Red Hat Enterprise Linux 7 nasm, nasm-rdoff
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.