CVE-2023-50781VulnerabilityPublished 5 Feb 2024Updated 20 Nov 2025

CVE-2023-50781: Timing Side Channel

Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.1% chance of exploitation in 30 days – higher than 66% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Feb 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

European organizations should take the following specific actions to mitigate CVE-2023-50781: 1) Identify all systems and applications using m2crypto for TLS, especially those configured with RSA key exchanges. 2) Monitor official m2crypto repositories and vendor advisories for patches or updates addressing this timing attack and apply them promptly. 3) Where possible, reconfigure TLS servers to use more secure key exchange algorithms such as ECDHE (Elliptic Curve Diffie-Hellman Ephemeral), which are not vulnerable to this timing discrepancy. 4) Implement network-level protections such as TLS interception detection and anomaly monitoring to identify suspicious traffic patterns indicative of timing attacks. 5) Conduct cryptographic audits and penetration testing focusing on TLS implementations to detect residual vulnerabilities. 6) Educate security teams about timing side-channel attacks and incorporate timing analysis into threat modeling. 7) For legacy systems that cannot be updated immediately, consider isolating or restricting access to reduce exposure. 8) Ensure robust logging and incident response plans are in place to quickly address any suspected exploitation attempts.

Description

A flaw was found in m2crypto. This issue may allow a remote attacker to decrypt captured messages in TLS servers that use RSA key exchanges, which may lead to exposure of confidential or sensitive data.

Impact

For European organizations, the primary impact of CVE-2023-50781 is the potential exposure of confidential or sensitive data transmitted over TLS connections that use RSA key exchanges with m2crypto. This could compromise privacy, intellectual property, or personal data protected under GDPR. Sectors such as finance, healthcare, government, and critical infrastructure that rely on secure communications are particularly at risk. The vulnerability allows remote attackers to decrypt intercepted TLS traffic, undermining trust in encrypted channels and potentially enabling further attacks or data breaches. Although the vulnerability does not affect integrity or availability, the confidentiality breach alone can lead to regulatory penalties, reputational damage, and operational disruptions. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits given the public disclosure. Organizations using legacy TLS configurations or custom applications with m2crypto should prioritize assessment and remediation to prevent data leakage.

Summary

CVE-2023-50781 is a cryptographic vulnerability identified in the m2crypto library, which is a Python wrapper for OpenSSL. The flaw arises from an observable timing discrepancy during the RSA key exchange process in TLS servers using m2crypto. An attacker who captures encrypted TLS traffic can analyze timing variations in the server's cryptographic operations to infer information about the RSA private key or plaintext messages. This side-channel attack exploits subtle differences in processing time that leak sensitive information, enabling decryption of captured messages without requiring direct access to the server or credentials. The vulnerability affects TLS configurations that rely on RSA key exchanges, which are less common today but still present in legacy systems. The CVSS 3.1 score of 7.5 reflects a high severity due to the remote network attack vector, no required privileges or user interaction, and a high impact on confidentiality. The vulnerability does not affect message integrity or availability, and no known public exploits have been reported yet. The flaw was reserved in December 2023 and published in February 2024, with Red Hat as the assigner. No specific affected versions or patches are listed, indicating that users should monitor for updates or advisories from m2crypto maintainers and related distributions.

References

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