CVE-2023-52323Network attack vector

RSA plaintext recovery via variable-time OAEP decoding

Published Jan 5, 2024 · Updated Jun 3, 2025

Side-channel leakage in PyCryptodome and pycryptodomex before 3.19.1 allows remote authenticated users to recover RSA plaintext. PKCS1_OAEP.decrypt validates the leading byte, label hash, delimiter position, and zero padding with data-dependent Python searches and loops rather than one constant-time padding check. Exploitation requires repeated access to an OAEP decryption oracle and timing or response distinctions for attacker-chosen ciphertexts; integrity and availability are unaffected.

CVSS severity7.1
High
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Side-channel leakage in PyCryptodome and pycryptodomex before 3.19.1 allows remote authenticated users to recover RSA plaintext. PKCS1_OAEP.decrypt validates the leading byte, label hash, delimiter position, and zero padding with data-dependent Python searches and loops rather than one constant-time padding check. Exploitation requires repeated access to an OAEP decryption oracle and timing or response distinctions for attacker-chosen ciphertexts; integrity and availability are unaffected.

The record

CVE
CVE-2023-52323
Published
Jan 5, 2024
Updated
Jun 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 5, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.1GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
5.3OSVCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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