Cyber Resilience

CVE-2023-5981

Redhat Linux 8.0 … 9.0

Published
28 November 2023
Modified
25 March 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.013 67th percentile
Risk Priority 48 floored blend · peak EPSS

Summary

CVE-2023-5981 is a medium-severity Observable Timing Discrepancy (CWE-208) vulnerability in Redhat Linux. Its CVSS base score is 5.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Password Guessing (T1110.001); ranked in the top 33% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-208CWE-203

Related Threats

MITRE ATT&CK Enterprise Techniques

T1110.001 Password Guessing Credential Access
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.
attack.mitre.org →
T1087 Account Discovery Discovery
Adversaries may attempt to get a listing of valid accounts, usernames, or email addresses on a system or within a compromised environment.
attack.mitre.org →
T1087.001 Local Account Discovery
Adversaries may attempt to get a listing of local system accounts.
attack.mitre.org →
T1087.002 Domain Account Discovery
Adversaries may attempt to get a listing of domain accounts.
attack.mitre.org →
T1087.003 Email Account Discovery
Adversaries may attempt to get a listing of email addresses and accounts.
attack.mitre.org →
T1087.004 Cloud Account Discovery
Adversaries may attempt to get a listing of cloud accounts.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-0361Same product: Debian Debian Linux
CVE-2024-0553Same product: Fedoraproject Fedora
CVE-2024-56738Same vendor: Gnu
CVE-2024-0567Same product: Debian Debian Linux
CVE-2023-25806Shared CWE-203, CWE-208
CVE-2023-32694Shared CWE-203, CWE-208
CVE-2024-1543Shared CWE-203, CWE-208
CVE-2024-41741Shared CWE-203, CWE-208
CVE-2026-41588Shared CWE-203, CWE-208
CVE-2026-23849Shared CWE-203, CWE-208

Affected Assets

debian
debian linux
10.0
gnu
gnutls
≤ 3.8.2
redhat
linux
8.0, 9.0
fedoraproject
fedora
37, 38

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V11.2.4

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-30 Concealment and Misdirection
addresses: CWE-203 CWE-208

Misdirection can normalize or falsify responses to eliminate observable discrepancies that aid reconnaissance.

SC-31 Covert Channel Analysis
addresses: CWE-208 CWE-203

Observable timing discrepancies are a primary mechanism for constructing covert timing channels; analysis identifies and bounds them, limiting exploitation.

SI-11 Error Handling
addresses: CWE-203

Prevents attackers from using observable differences in error responses to infer internal system details or state.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require constant-time implementations that eliminate observable timing discrepancies.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.17 Clock synchronization none match
none

Consistent reference clocks limit the attacker's ability to measure or manipulate timing differences that could reveal internal state or processing paths.

References