CVE-2025-59438Network attack vector

Plaintext recovery via padding-oracle timing

Published Oct 21, 2025 · Updated Oct 21, 2025

Observable timing discrepancy in Mbed TLS 3.6.4 and earlier allows attackers to recover plaintext via chosen ciphertexts. PSA error translation and certain driver paths distinguish valid from invalid padding through observable execution timing. Exploitation requires padded CBC or ECB decryption and a padding-validity timing oracle; authenticated ciphertext-only handling prevents exposure.

CVSS severity5.3
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable timing discrepancy in Mbed TLS 3.6.4 and earlier allows attackers to recover plaintext via chosen ciphertexts. PSA error translation and certain driver paths distinguish valid from invalid padding through observable execution timing. Exploitation requires padded CBC or ECB decryption and a padding-validity timing oracle; authenticated ciphertext-only handling prevents exposure.

The record

CVE
CVE-2025-59438
Published
Oct 21, 2025
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-208
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-208Observable Timing Discrepancy

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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