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Fencer Vulns
medium 5.5

CVE-2020-28928 json

In musl libc through 1.2.1, wcsnrtombs mishandles particular combinations of destination buffer size and source character limit, as demonst…

published 2020-11-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-21316

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 51%
public exploits
0
none known

Summary

In musl libc through 1.2.1, wcsnrtombs mishandles particular combinations of destination buffer size and source character limit, as demonstrated by an invalid write access (buffer overflow).

Patch / fix

  • musl Debian 14, Debian 13, Debian 12 1.2.2-1

debian advisories DEBIAN-CVE-2020-28928

  • musl Ubuntu Pro 14.04 LTS 0.9.15-1ubuntu0.1~esm2
  • musl Ubuntu Pro 16.04 LTS 1.1.9-1ubuntu0.1~esm3
  • musl Ubuntu Pro 18.04 LTS 1.1.19-1ubuntu0.1~esm1
  • musl Ubuntu Pro 20.04 LTS 1.1.24-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2020-28928

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • musl Alpine 3.10 1.1.22-r4
  • musl Alpine 3.11 1.1.24-r3
  • musl Alpine 3.12 1.1.24-r10
  • musl Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 1.2.2_pre2-r0
  • musl Alpine 3.9 1.1.20-r6

alpine advisories ALPINE-CVE-2020-28928

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • musl Arch Linux 1.2.1-2

arch linux advisories AVG-1287

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-2020-28928 updated cvss 5.3

musl: infinite loop in wcsnrtombs function

  • Red Hat All currently supported Red Hat products
    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

0.65% chance of exploitation in the next 30 days, higher than 51% 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:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:N/I:N/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.