CVE-2021-43527 Memory corruption in NSS

Q: Is CVE-2021-43527 being exploited?

There is no known exploitation of CVE-2021-43527 in the wild and no public exploit code.

Critical 9.8 Published 8 Dec 2021 Updated 4 Aug 2024

Heap overflow in NSS allows code execution when processing malicious DER-encoded signatures in email or document viewers.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2021-43527?

CVE-2021-43527 is a critical memory corruption vulnerability in Netapp Cloud Backup, published on 8 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-787

Which versions are affected by CVE-2021-43527?

It affects 10 products.

Linux distribution packages (40)

`nss` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-devel` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-softokn` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-softokn-devel` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-softokn-freebl` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-softokn-freebl-devel` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-sysinit` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-tools` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-util` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss-util-devel` AlmaLinux:8	All versions	`3.67.0-7.el8_5`
`nss` Red Hat:enterprise_linux:7::client	All versions	`0:3.67.0-4.el7_9`
`nss-debuginfo` Red Hat:enterprise_linux:7::client	All versions	`0:3.67.0-4.el7_9`
`nss-devel` Red Hat:enterprise_linux:7::client	All versions	`0:3.67.0-4.el7_9`
`nss-pkcs11-devel` Red Hat:enterprise_linux:7::client	All versions	`0:3.67.0-4.el7_9`
`nss-sysinit` Red Hat:enterprise_linux:7::client	All versions	`0:3.67.0-4.el7_9`
`nss-tools` Red Hat:enterprise_linux:7::client	All versions	`0:3.67.0-4.el7_9`
`nss-debuginfo` Red Hat:enterprise_linux:7::computenode	All versions	`0:3.67.0-4.el7_9`
`nss-devel` Red Hat:enterprise_linux:7::computenode	All versions	`0:3.67.0-4.el7_9`
`nss-pkcs11-devel` Red Hat:enterprise_linux:7::computenode	All versions	`0:3.67.0-4.el7_9`
`nss` Red Hat:enterprise_linux:7::server	All versions	`0:3.67.0-4.el7_9`
`nss-debuginfo` Red Hat:enterprise_linux:7::server	All versions	`0:3.67.0-4.el7_9`
`nss-devel` Red Hat:enterprise_linux:7::server	All versions	`0:3.67.0-4.el7_9`
`nss-pkcs11-devel` Red Hat:enterprise_linux:7::server	All versions	`0:3.67.0-4.el7_9`
`nss-sysinit` Red Hat:enterprise_linux:7::server	All versions	`0:3.67.0-4.el7_9`
`nss-tools` Red Hat:enterprise_linux:7::server	All versions	`0:3.67.0-4.el7_9`
`nss` Red Hat:enterprise_linux:7::workstation	All versions	`0:3.67.0-4.el7_9`
`nss-debuginfo` Red Hat:enterprise_linux:7::workstation	All versions	`0:3.67.0-4.el7_9`
`nss-devel` Red Hat:enterprise_linux:7::workstation	All versions	`0:3.67.0-4.el7_9`
`nss-pkcs11-devel` Red Hat:enterprise_linux:7::workstation	All versions	`0:3.67.0-4.el7_9`
`nss-sysinit` Red Hat:enterprise_linux:7::workstation	All versions	`0:3.67.0-4.el7_9`
`nss-tools` Red Hat:enterprise_linux:7::workstation	All versions	`0:3.67.0-4.el7_9`
`nss` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-debuginfo` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-debugsource` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-devel` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-softokn` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-softokn-debuginfo` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-softokn-devel` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-softokn-freebl` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`
`nss-softokn-freebl-debuginfo` Red Hat:enterprise_linux:8::appstream	All versions	`0:3.67.0-7.el8_5`

Products include Mozilla Nss, Mozilla Nss Esr, Netapp Cloud Backup, Netapp E-Series Santricity Os Controller, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Repository Function and 4 more.

How do I fix CVE-2021-43527?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-43527 being exploited?

There is no known exploitation of CVE-2021-43527 in the wild and no public exploit code.

All Netapp Cloud Backup vulnerabilities

Sources

Also known as ALPINE-CVE-2021-43527, ALSA-2021:4903, AZL-7024, CLSA-2021-1638804170, CLSA-2021-1639578644, CLSA-2021-1640002354 and 32 more.