Skip to content
Fencer Vulns
medium 6.5

CVE-2021-45931 json

HarfBuzz 2.9.0 has an out-of-bounds write in hb_bit_set_invertible_t::set (called from hb_sparseset_t<hb_bit_set_invertible_t>::set and hb_…

published 2021-12-31 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-32640

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

HarfBuzz 2.9.0 has an out-of-bounds write in hb_bit_set_invertible_t::set (called from hb_sparseset_t<hb_bit_set_invertible_t>::set and hb_set_copy).

Patch / fix

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-2021-45931 updated cvss 6.3

harfbuzz: out-of-bounds write in hb_bit_set_invertible_t::set

  • Red Hat Enterprise Linux 6 firefox, autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, +62 more Red Hat Enterprise Linux 7 harfbuzz, harfbuzz-icu Red Hat Enterprise Linux 8 harfbuzz, harfbuzz-icu, mingw32-harfbuzz, mingw64-harfbuzz Red Hat Enterprise Linux 9 harfbuzz, harfbuzz-icu
    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

1.84% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/google/oss-fuzz-vulns/blob/main/vulns/harfbuzz/OSV-2021-1159.yaml referenced PoC, tagged "exploit" by a source, unverified
  • bugs.chromium.org https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=37425 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/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

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.