CVE-2025-7071

Plaintext recovery via nonconstant-time padding validation

Published Aug 29, 2025 · Updated Aug 29, 2025

Timing side channel in ocrypto 3.1.0 through 3.9.1 allows attackers to recover plaintext via AES-CBC PKCS#7 decryption probes. The ocrypto_aes_cbc_pkcs_final_dec function in ocrypto_aes_cbc_pkcs.c takes measurably different time for valid padding and padding errors. Exploitation requires attackers to submit thousands of chosen ciphertexts and measure decryption timing, enabling message-length discovery and byte-by-byte recovery of the full plaintext.

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 ocrypto 3.1.0 through 3.9.1 allows attackers to recover plaintext via AES-CBC PKCS#7 decryption probes. The ocrypto_aes_cbc_pkcs_final_dec function in ocrypto_aes_cbc_pkcs.c takes measurably different time for valid padding and padding errors. Exploitation requires attackers to submit thousands of chosen ciphertexts and measure decryption timing, enabling message-length discovery and byte-by-byte recovery of the full plaintext.

The record

CVE
CVE-2025-7071
Published
Aug 29, 2025
Updated
Aug 29, 2025
Vendor
Oberon microsystems AG
Product
ocrypto
Classifications
CWE-208, CWE-327
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=3.1.0 <=3.9.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Oberon microsystems AG · ocryptoversion=3.1.0 <=3.9.1

Published CVSS scores

5.9Switzerland Government Common Vulnerability ProgramCVSS: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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-208Observable Timing Discrepancy
CWE-327Use of a Broken or Risky Cryptographic Algorithm

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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