CVE-2026-55961Network attack vector

Signature bypass via empty PKCS7 signerInfos

Published Jun 25, 2026 · Updated Jun 25, 2026

Improper signature verification in wolfSSL 3.15.7 through 5.9.1 allows attackers to pass unsigned content as verified via degenerate PKCS#7 bundles. wolfSSL_PKCS7_verify() treats empty signerInfos as successful signed-data verification without authenticating any content. Reachability requires an OpenSSL compatibility build whose application passes attacker-controlled bundles to PKCS7_verify(); the result is acceptance of unauthenticated content.

CVSS severity8.2
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in wolfSSL 3.15.7 through 5.9.1 allows attackers to pass unsigned content as verified via degenerate PKCS#7 bundles. wolfSSL_PKCS7_verify() treats empty signerInfos as successful signed-data verification without authenticating any content. Reachability requires an OpenSSL compatibility build whose application passes attacker-controlled bundles to PKCS7_verify(); the result is acceptance of unauthenticated content.

The record

CVE
CVE-2026-55961
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
wolfSSL
Product
wolfSSL
Classifications
CWE-347, T1553
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record 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=3.15.7 <=5.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

wolfSSL · wolfSSLversion=3.15.7 <=5.9.1

Published CVSS scores

8.2wolfSSL Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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-347Improper Verification of Cryptographic Signature
T1553Subvert Trust Controls

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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