CVE-2023-5981: Gnutls: timing side-channel in the rsa-psk authentication

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-11-28 · updated 2026-10-14
Weakness: CWE-208

Description

A vulnerability was found that the response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from response times of ciphertexts with correct PKCS#1 v1.5 padding.

Affected products

Debian Linux: 10.0
Fedoraproject Fedora: 37, 38
[UNKNOWN] gnutls: before 3.8.2 — fixed in 3.8.2
RedHat Linux: 8.0, 9.0

How to fix

Upgrade to a fixed version: [UNKNOWN] gnutls 3.8.2. Check the vendor advisory for mitigations.

References

https://access.redhat.com/errata/RHSA-2024:0155
https://access.redhat.com/errata/RHSA-2024:0319
https://access.redhat.com/errata/RHSA-2024:0399
https://access.redhat.com/errata/RHSA-2024:0451
https://access.redhat.com/errata/RHSA-2024:0533
https://access.redhat.com/errata/RHSA-2024:1383
https://access.redhat.com/errata/RHSA-2024:2094
https://access.redhat.com/security/cve/CVE-2023-5981
https://bugzilla.redhat.com/show_bug.cgi?id=2248445
https://gnutls.org/security-new.html#GNUTLS-SA-2023-10-23
http://www.openwall.com/lists/oss-security/2024/01/19/3
https://access.redhat.com/errata/RHSA-2024:0155

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