---
id: CVE-2023-5981
title: >-
  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.
summary: >-
  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.
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-208
  - CWE-203
vendor: gnu
product: gnutls
affected:
  - debian_linux = 10.0
  - gnutls < 3.8.2
  - linux = 8.0
  - linux = 9.0
  - fedora = 37
  - fedora = 38
patched:
  - gnutls 3.8.2
published: '2023-11-28'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T22:17:21.480'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-5981'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2024:0155'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2024:0319'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2024:0399'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2024:0451'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2024:0533'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2024:1383'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2024:2094'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2023-5981'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2248445'
    label: secalert@redhat.com
  - url: 'https://gnutls.org/security-new.html#GNUTLS-SA-2023-10-23'
    label: secalert@redhat.com
  - url: 'http://www.openwall.com/lists/oss-security/2024/01/19/3'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:0155'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:0319'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:0399'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:0451'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:0533'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:1383'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/errata/RHSA-2024:2094'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://access.redhat.com/security/cve/CVE-2023-5981'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2248445'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://gnutls.org/security-new.html#GNUTLS-SA-2023-10-23'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2023/11/msg00016.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7ZEIOLORQ7N6WRPFXZSYDL2MC4LP7VFV/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GNXKVR5YNUEBNHAHM5GSYKBZX4W2HMN2/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.01267
epssPercentile: 0.69201
ingestedAt: '2026-10-14T23:00:02.007Z'
---

## Overview

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

- `debian_linux = 10.0`
- `gnutls < 3.8.2`
- `linux = 8.0`
- `linux = 9.0`
- `fedora = 37`
- `fedora = 38`

## Remediation

Upgrade past the affected range:

- `gnutls 3.8.2`