VulnerabilityPublished 5 Jan 2024Updated 3 Jun 2025

CVE-2023-52323: PyCryptodome · Observable Discrepancy

Source CVE Database V5

Not known to be exploited · CVSS 5.9 Medium : upgrade to 3.19.1 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.9Medium

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.19.1

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

Attack Vector: Network
Attack Complexity: High
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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 Jan 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 26 Oct 2026.

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 or the CVSS exploit maturity 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

Upgrade pycryptodome and pycryptodomex to 3.19.1.

Affected software

Product	Affected	Fixed in
PyPIpycryptodome`pkg:pypi/pycryptodome`Other threats	Affected <3.19.1	Fixed in 3.19.1
PyPIpycryptodomex`pkg:pypi/pycryptodomex`Other threats	Affected <3.19.1	Fixed in 3.19.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should take the following specific mitigation steps: 1) Identify all Python applications and services using PyCryptodome or pycryptodomex libraries, especially those performing RSA-OAEP decryption. 2) Upgrade these libraries to version 3.19.1 or later, where the vulnerability is fixed. 3) Review application code to ensure that decryption operations are not exposed to untrusted or attacker-controlled ciphertext inputs. 4) Implement additional cryptographic best practices such as limiting the exposure of decryption endpoints, applying rate limiting, and monitoring for anomalous decryption requests that could indicate an attempted Manger attack. 5) Conduct code audits and penetration testing focused on cryptographic operations to detect any side-channel leakage or improper error handling. 6) For critical systems, consider using hardware security modules (HSMs) or cryptographic libraries with proven side-channel resistance. 7) Maintain up-to-date threat intelligence and vulnerability management processes to quickly respond to any emerging exploits related to this vulnerability.

Description

PyCryptodome and pycryptodomex before 3.19.1 allow side-channel leakage for OAEP decryption, exploitable for a Manger attack.

Impact

For European organizations, the impact of CVE-2023-52323 can be significant, particularly for those relying on Python applications that use PyCryptodome or pycryptodomex for RSA-OAEP encryption/decryption. Confidentiality of sensitive data such as personal information, intellectual property, or cryptographic keys could be compromised if attackers exploit the side-channel leakage. This is especially critical for sectors like finance, healthcare, government, and critical infrastructure, where encrypted data protection is paramount under regulations like GDPR. Although the attack complexity is high and no known exploits exist yet, the vulnerability allows remote exploitation without authentication or user interaction, increasing the risk profile. Organizations using these libraries in web services, APIs, or cloud environments where attacker-controlled ciphertexts might be submitted are at higher risk. The vulnerability does not affect data integrity or availability, but the loss of confidentiality could lead to data breaches, regulatory penalties, and reputational damage. The medium severity rating suggests that while the threat is not immediately critical, it requires timely attention to prevent potential exploitation.

CWE-203Observable Discrepancy (opens in a new tab)
Base weakness
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended).
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Black Box Reverse Engineering (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Jul 2025, 02:26 UTC

WeaknessesCWE-203

Technical details

References

Community reviews

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