Vulnerability · CVE-2023-5981
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.
Published Nov 28, 2023 · catalog updated Oct 14, 2026 · debian linux
Check if you run it
No confirmed exploitation is on record for CVE-2023-5981. EPSS is 1.27%. Act only if a listed version of debian linux is installed.
Gaps on this record
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium5.9
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 1.27%
- Remediation
- Advisory link
- Affected products
- cpe debian/debian linux · cpe fedoraproject/fedora · cpe gnu/gnutls · cpe redhat/linux
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe debian/debian linux10.0
- cpe fedoraproject/fedora37
- cpe fedoraproject/fedora38
- cpe gnu/gnutlsversion unspecified
- cpe redhat/linux8.0
- cpe redhat/linux9.0
How to fix CVE-2023-5981
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2023-5981. EPSS is 1.27%. Act only if a listed version of debian linux is installed.
Which versions are affected?
Compare what you have installed with debian/debian linux 10.0. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-203: Observable Discrepancy; CWE-208. EPSS 1.27%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Nov 28, 2023 · NIST NVD
Detected
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.
Oct 14, 2026 · NIST NVD
Updated
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.
Sources
- CVE.orgVulnerability recordCVE-2023-5981
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2023-5981
30-day exploitation probability 1.3%
first.org - NIST NVDVulnerability recordCVE-2023-5981
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.
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.