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CVE-2026-94418

7.5, high

Under WOLFSSL_SMALL_CERT_VERIFY, ProcessPeerCertParse() runs the certificate signature check separately from the parse to keep peak…

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
7.5, high high CVSS v3.1
EPSS, next 30 days
<0.1% higher than 0.5% of scored CVEs
Exploitation
No public evidence
Published
27 Sept 202620 days ago

Description

Under WOLFSSL_SMALL_CERT_VERIFY, ProcessPeerCertParse() runs the certificate signature check separately from the parse to keep peak memory down, then merges the two results, but it merged the signature result back only when the parse returned 0, so any parse error hid it. ParseCertRelative() reaches its validity-date, name-constraint and critical-extension checks only after ConfirmSignature() has passed, so splitting the signature check out inverts the precedence that makes "override date errors" a sound policy, and ASN_SIG_CONFIRM_E is never surfaced anywhere. The attacker needs no key material from the real PKI and no CA compromise: a self-made certificate carrying the expected subject name, the trusted CA's subject as its issuer, arbitrary bytes where the signature goes, a validity window in the past and the attacker's own key pair is sufficient. Affected builds define WOLFSSL_SMALL_CERT_VERIFY, which is off by default, is not set implicitly by any platform or preset header, and is not reachable from any CMake option; the autotools routes are --enable-lowresource, --enable-leantls, --enable-tinytls13=cert and --enable-tinytls13=mutualauth, and examples/configs/user_settings_embedded.h reaches it through WC_CFG_SMALL_CERT_VERIFY, which ships as 0, while neither --enable-all nor --enable-distro enables it at all. The application must additionally install a verify callback through wolfSSL_CTX_set_verify() or wolfSSL_set_verify() with WOLFSSL_VERIFY_PEER that returns 1 for ASN_BEFORE_DATE_E or ASN_AFTER_DATE_E; wolfSSL ships this exact shape as myVerify() in wolfssl/test.h under VERIFY_OVERRIDE_DATE_ERR, which examples/client -D selects. An application with no callback, or whose callback returns preverify for date errors, still fails the handshake, and wolfSSL_CertManagerVerifyBuffer() and wc_CheckCertSignature() report ASN_SIG_CONFIRM_E correctly in the same binary. TLS 1.2 and TLS 1.3 are affected in both directions, and DTLS reaches the same function; where the forged certificate is a chain certificate the callback's consent causes it to be cached in the WOLFSSL_CTX certificate manager, so an exposed deployment must restart the context or the process rather than merely reconnect.

Details

Vendor
wolfSSL
Product
wolfSSL
Weakness
CWE-347 (opens in a new tab)
Status
Analyzed
Updated
2 Oct 2026
Assigner
facts@wolfssl.com

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

References 1

Patches and fixes 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other wolfSSL CVEs

Every wolfSSL CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-83540 wolfSSL wolfSSH Improper Authentication Vulnerability EPSS 0.4% 8.8, high
  • CVE-2026-89134 A certificate with no dNSName SAN but another SAN type present (e.g EPSS 0.2% 9.1, critical
  • CVE-2026-93302 MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification EPSS 0.2% 8.2, high

Beyond this page

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Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.