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Fencer Vulns
critical 9.8

CVE-2020-24978 json

In NASM 2.15.04rc3, there is a double-free vulnerability in pp_tokline asm/preproc.c.

published 2020-09-03 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-17678

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

In NASM 2.15.04rc3, there is a double-free vulnerability in pp_tokline asm/preproc.c. This is fixed in commit 8806c3ca007b84accac21dd88b900fb03614ceb7.

Patch / fix

  • nasm Debian 14, Debian 13, Debian 12 2.15.04-1

debian advisories DEBIAN-CVE-2020-24978

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-2020-24978 updated cvss 5.5

nasm: double-free vulnerability in pp_tokline asm/preproc.c

  • Red Hat Enterprise Linux 5 nasm Red Hat Enterprise Linux 6 nasm, nasm-rdoff
    affected: no fix planned “Out of support scope”
  • 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

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.nasm.us https://bugzilla.nasm.us/show_bug.cgi?id=3392712 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

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.