Dear all, We just released NSS 3.73 and NSS 3.68.1(ESR). Those versions contain the fix for CVE-2021-43527 which affected previous versions. The release notes for those versions of NSS will follow on this list shortly.
Best, Benjamin https://www.mozilla.org/en-US/security/advisories/mfsa2021-51/ <https://www.mozilla.org/en-US/security/advisories/mfsa2021-51/> CVE-2021-43527: Heap overflow in NSS when verifying DSA/RSA-PSS DER-encoded signatures Summary: NSS (Network Security Services) versions prior to 3.73 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. This vulnerability does NOT impact Mozilla Firefox, Tor Browser or Chromium. However, other applications that use NSS for signature verification are likely to be impacted. Technical Details: When verifying a DER-encoded signature, NSS decodes the signature into a fixed-size buffer and passes the buffer to the underlying PKCS #11 module. The length of the signature is not correctly checked when processing DSA and RSA-PSS signatures. DSA and RSA-PSS signatures larger than 16384 bits will overflow the buffer in VFYContextStr. The vulnerable code is located within secvfy.c:vfy_CreateContext. Test cases are attached (tests.zip) and can be tested using the vfychain tool shipped with NSS. Running `vfychain -a {input.cert}` will cause a segfault on vulnerable versions and a failed verification on fixed versions. Remediation: NSS 3.73 [1] and NSS ESR 3.68.1 [2] have been released and contain the fix. A patch suitable for backporting is also attached (patch.diff). Acknowledgements: This vulnerability was reported to the NSS team by Tavis Ormandy of Project Zero. Thanks to all the the NSS team members in all companies and the Security Engineering team for its precious help in the fix and disclosure of this issue. -- You received this message because you are subscribed to the Google Groups "dev-tech-crypto@mozilla.org" group. To unsubscribe from this group and stop receiving emails from it, send an email to dev-tech-crypto+unsubscr...@mozilla.org. To view this discussion on the web visit https://groups.google.com/a/mozilla.org/d/msgid/dev-tech-crypto/D9C189DF-4362-471F-96A6-B7C77618C507%40mozilla.com.
