CVE-2025-52556Public exploitNetwork attack vector

Timestamp forgery via omitted PKCS7 signature verification

Published Jun 21, 2025 · Updated Jun 23, 2025

Improper signature verification in Trail of Bits rfc3161-client before 1.0.3 allows remote attackers to forge trusted timestamp responses. The pkcs7_verify path validates the embedded signer certificate chain but returns success without checking the PKCS7 signature over the response. Exploitation requires a crafted response containing a leaf certificate that chains to a trusted root; acceptance can falsely authenticate timestamped data and its asserted origin.

CVSS severity9.3
Critical
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper signature verification in Trail of Bits rfc3161-client before 1.0.3 allows remote attackers to forge trusted timestamp responses. The pkcs7_verify path validates the embedded signer certificate chain but returns success without checking the PKCS7 signature over the response. Exploitation requires a crafted response containing a leaf certificate that chains to a trusted root; acceptance can falsely authenticate timestamped data and its asserted origin.

The record

CVE
CVE-2025-52556
Published
Jun 21, 2025
Updated
Jun 23, 2025
Vendor
Trail of Bits
Product
rfc3161-client
Classifications
CWE-347
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 1.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Trail of Bits · rfc3161-clientversion=< 1.0.3

Published CVSS scores

9.3GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo