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Fencer Vulns
medium 5.5

CVE-2018-19755 json

There is an illegal address access at asm/preproc.c (function: is_mmacro) in Netwide Assembler (NASM) 2.14rc16 that will cause a denial of…

published 2018-11-30 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-11439

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

There is an illegal address access at asm/preproc.c (function: is_mmacro) in Netwide Assembler (NASM) 2.14rc16 that will cause a denial of service (out-of-bounds array access) because a certain conversion can result in a negative integer.

Patch / fix

  • nasm Debian 14, Debian 13, Debian 12 2.15.02-1

debian advisories DEBIAN-CVE-2018-19755

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-2018-19755 updated cvss 7.0

nasm: out-of-bounds array access in is_mmacro in asm/preproc.c

  • Red Hat Enterprise Linux 5 nasm Red Hat Enterprise Linux 6 nasm, nasm-rdoff
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 nasm, nasm-rdoff
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 8 nasm
    affected: no fix planned “Will not fix”

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

1.00% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • repo.or.cz https://repo.or.cz/nasm.git/commit/3079f7966dbed4497e36d5067cbfd896a90358cb referenced PoC, tagged "exploit" by a source, unverified
  • bugzilla.nasm.us https://bugzilla.nasm.us/show_bug.cgi?id=3392528 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/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-20 Improper Input Validation

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.