9.8

CVE-2021-43527: mozilla nss Out-of-bounds Write

Modified
AliasesALPINE-CVE-2021-43527MGASA-2021-0534SUSE-SU-2021:14858-1
Published 08-12-2021Last modified 04-08-2024

Vulnerability summary

CVE-2021-43527 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in mozilla nss. EPSS estimates a 17.56% chance of exploitation in the next 30 days, higher than 97.1% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.8 (NVD); no exploitation reported by the 5 checked sources; EPSS 18% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
17.56%
0%100%
Medium · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 10 · Related 9
RHSA-2021:5035SUSE-SU-2024:2008-1SUSE-SU-2024:2010-1SUSE-SU-2024:2011-1SUSE-SU-2024:2019-1SUSE-SU-2024:2183-1

Timeline

  1. 08-12-2021
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

Description

NSS (Network Security Services) versions prior to 3.73 or 3.68.1 ESR are vulnerable to a heap overflow when handling DER-encoded DSA or RSA-PSS signatures. Applications using NSS for handling signatures encoded within CMS, S/MIME, PKCS \#7, or PKCS \#12 are likely to be impacted. Applications using NSS for certificate validation or other TLS, X.509, OCSP or CRL functionality may be impacted, depending on how they configure NSS. *Note: This vulnerability does NOT impact Mozilla Firefox.* However, email clients and PDF viewers that use NSS for signature verification, such as Thunderbird, LibreOffice, Evolution and Evince are believed to be impacted. This vulnerability affects NSS < 3.73 and NSS < 3.68.1.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

17.56%

Chance of exploitation in the next 30 days

Percentile

97%

Versus all other CVEs

30-day change

No change 0.00 pp

From 17.56% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Suse41 products
  • mozilla-nspr&distro=SUSE Linux Enterprise Server 12 SP2-BCL< 4.34-19.21.1
  • mozilla-nspr&distro=SUSE Linux Enterprise Server 12 SP3-BCL< 4.34-19.21.1
  • mozilla-nspr&distro=SUSE Linux Enterprise Server 12 SP4-LTSS< 4.34-19.21.1
  • mozilla-nspr&distro=SUSE Linux Enterprise Server 12 SP5< 4.34-19.21.1
  • mozilla-nspr&distro=SUSE Linux Enterprise Server for SAP Applications 12 SP4< 4.34-19.21.1
Redhat23 products
  • nss< 0:3.67.0-7.el8_5 | < 0:3.67.0-4.el7_9 | < 0:3.44.0-12.el6_10 | < 0:3.67.0-7.el8_4 | < 0:3.53.1-12.el8_2 | < 0:3.28.4-18.el7_4 | < 0:3.36.0-10.2.el7_6 | < 0:3.44.0-8.el7_7 | < 0:3.44.0-10.el8_1 | < 0:3.28.4-2.el7_3
  • nss-debuginfo< 0:3.67.0-7.el8_5 | < 0:3.67.0-4.el7_9 | < 0:3.44.0-12.el6_10 | < 0:3.67.0-7.el8_4 | < 0:3.53.1-12.el8_2 | < 0:3.28.4-18.el7_4 | < 0:3.36.0-10.2.el7_6 | < 0:3.44.0-8.el7_7 | < 0:3.44.0-10.el8_1 | < 0:3.28.4-2.el7_3
  • nss-debugsource< 0:3.67.0-7.el8_5 | < 0:3.67.0-7.el8_4 | < 0:3.53.1-12.el8_2 | < 0:3.44.0-10.el8_1
  • nss-devel< 0:3.67.0-7.el8_5 | < 0:3.67.0-4.el7_9 | < 0:3.44.0-12.el6_10 | < 0:3.67.0-7.el8_4 | < 0:3.53.1-12.el8_2 | < 0:3.28.4-18.el7_4 | < 0:3.36.0-10.2.el7_6 | < 0:3.44.0-8.el7_7 | < 0:3.44.0-10.el8_1 | < 0:3.28.4-2.el7_3
  • nss-pkcs11-devel< 0:3.67.0-4.el7_9 | < 0:3.44.0-12.el6_10 | < 0:3.28.4-18.el7_4 | < 0:3.36.0-10.2.el7_6 | < 0:3.44.0-8.el7_7 | < 0:3.28.4-2.el7_3
Oracle4 products
Mozilla2 products
  • nss≥ unspecified, < 3.73 | ≥ unspecified, < 3.68.1 | < 3.73
  • nss_esr< 3.68.1
Netapp2 products
Opensuse2 products
  • mozilla-nss&distro=openSUSE Leap 15.3< 3.68.1-3.61.1
  • mozilla-nss&distro=openSUSE Tumbleweed< 3.73-1.1
Starwindsoftware2 products
Ubuntu2 products
  • nss< 2:3.68-1ubuntu2 | < 2:3.35-2ubuntu2.13 | < 2:3.49.1-1ubuntu1.6 | < 2:3.28.4-0ubuntu0.14.04.5+esm9 | < 2:3.28.4-0ubuntu0.16.04.14+esm1 | < 2:3.28.4-0ubuntu0.14.04.5+esm10 | < 2:3.28.4-0ubuntu0.16.04.14+esm2
  • thunderbird< 1:91.4.0+build1.1-0ubuntu1 | < 1:78.14.0+build1-0ubuntu0.18.04.2 | < 1:78.14.0+build1-0ubuntu0.20.04.2
Alpine1 product
  • nss< 3.60-r2 | < 3.66-r0 | < 3.72-r1 | < 3.73-r0
Debian1 product
  • nss< 2:3.42.1-1+deb10u4 | < 2:3.61-1+deb11u1 | < 2:3.26.2-1.1+deb9u3 | < 2:3.73-1
Mageia1 product
  • nss< 3.73.0-1.mga8

11 vendors · 81 products

References

71 links
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