CVE-2025-7383

Plaintext recovery via non-constant-time PKCS#7 padding checks

Published Aug 29, 2025 · Updated Aug 29, 2025

Timing side channel in Oberon PSA Crypto 1.0.0 through 1.5.0 allows attackers to recover AES-CBC plaintext via crafted padding probes. The psa_cipher_finish function in psa_crypto.c and corresponding driver code in oberon_cipher.c distinguish valid from invalid PKCS#7 padding with non-constant-time processing. Exploitation requires sending thousands of chosen ciphertexts and measuring response timing, revealing message length and then plaintext byte by byte.

CVSS severity5.9
Medium
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timing side channel in Oberon PSA Crypto 1.0.0 through 1.5.0 allows attackers to recover AES-CBC plaintext via crafted padding probes. The psa_cipher_finish function in psa_crypto.c and corresponding driver code in oberon_cipher.c distinguish valid from invalid PKCS#7 padding with non-constant-time processing. Exploitation requires sending thousands of chosen ciphertexts and measuring response timing, revealing message length and then plaintext byte by byte.

The record

CVE
CVE-2025-7383
Published
Aug 29, 2025
Updated
Aug 29, 2025
Vendor
Oberon microsystems AG
Product
Oberon PSA Crypto
Classifications
CWE-327, CWE-208, CAPEC-463
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.0 <=1.5.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Oberon microsystems AG · Oberon PSA Cryptoversion=1.0.0 <=1.5.0

Published CVSS scores

5.9Switzerland National Cyber Security CentreCVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
CWE-208Observable Timing Discrepancy
CAPEC-463Padding Oracle Crypto Attack

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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