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Full vulnerability report · 2026
CVE-2026-93302High confidence

Trusted peer certificate match ignores public key, allowing forged CA clones

wolfSSL · wolfSSL

8.3HighCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 3 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.20% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs wolfSSL wolfSSL and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 3 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

4 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 3 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcewolfsslAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 7 Oct 2026
Debian bookwormbookworm · sourcewolfsslAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 7 Oct 2026
Debian sidsid · sourcewolfsslAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 7 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivewolfsslUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 7 Oct 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-87910

No EUVD known-exploited evidence

MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification. Affected builds are any that enable the macro WOLFSSL_TRUST_PEER_CERT and load CA certificates with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert(). The peer must know the certificates being loaded to either of those APIs to take advantage of the issue. When OPENSSL_COMPATIBLE_DEFAULTS is also defined this widens the affected API to include all CA certificate loading. Both macros are defined when using autoconf builds such as (nginx, haproxy, stunnel, wpas, apache httpd, hitch, bind, rsyslog, ffmpeg, all, distro). When the certificate is listed as a trusted peer certificate the issue previously allowed for a malicious (D)TLS server to bypass authentication once knowing which CA’s the client would accept. This also affects mutual authentication cases where the client knows which CA’s the server has loaded. If building with any of these configurations and using (D)TLS where the loaded CA’s could be known and authentication of the peer is desired, users should either: update to the latest wolfSSL version, apply the fix patch, or use the configure flag --disable-openssl-compatible-defaults and not load CA’s with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert() to mitigate the issue.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
8.3 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 3 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification. Affected builds are any that enable the macro WOLFSSL_TRUST_PEER_CERT and load CA certificates with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert(). The peer must know the certificates being loaded to either of those APIs to take advantage of the issue. When OPENSSL_COMPATIBLE_DEFAULTS is also defined this widens the affected API to include all CA certificate loading. Both macros are defined when using autoconf builds such as (nginx, haproxy, stunnel, wpas, apache httpd, hitch, bind, rsyslog, ffmpeg, all, distro). When the certificate is listed as a trusted peer certificate the issue previously allowed for a malicious (D)TLS server to bypass authentication once knowing which CA’s the client would accept. This also affects mutual authentication cases where the client knows which CA’s the server has loaded. If building with any of these configurations and using (D)TLS where the loaded CA’s could be known and authentication of the peer is desired, users should either: update to the latest wolfSSL version, apply the fix patch, or use the configure flag --disable-openssl-compatible-defaults and not load CA’s with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert() to mitigate the issue.

What

MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification. Affected builds are any that enable the macro WOLFSSL_TRUST_PEER_CERT and load CA certificates with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert(). The peer must know the certificates being loaded to either of those APIs to take advantage of the issue. When OPENSSL_COMPATIBLE_DEFAULTS is also defined this widens the affected API to include all CA certificate loading. Both macros are defined when using autoconf builds such as (nginx, haproxy, stunnel, wpas, apache httpd, hitch, bind, rsyslog, ffmpeg, all, distro). When the certificate is listed as a trusted peer certificate the issue previously allowed for a malicious (D)TLS server to bypass authentication once knowing which CA’s the client would accept. This also affects mutual authentication cases where the client knows which CA’s the server has loaded. If building with any of these configurations and using (D)TLS where the loaded CA’s could be known and authentication of the peer is desired, users should either: update to the latest wolfSSL version, apply the fix patch, or use the configure flag --disable-openssl-compatible-defaults and not load CA’s with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert() to mitigate the issue.

Why

The product does not validate, or incorrectly validates, a certificate.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification. Affected builds are any that enable the macro WOLFSSL_TRUST_PEER_CERT and load CA certificates with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert(). The peer must know the certificates being loaded to either of those APIs to take advantage of the issue. When OPENSSL_COMPATIBLE_DEFAULTS is also defined this widens the affected API to include all CA certificate loading. Both macros are defined when using autoconf builds such as (nginx, haproxy, stunnel, wpas, apache httpd, hitch, bind, rsyslog, ffmpeg, all, distro). When the certificate is listed as a trusted peer certificate the issue previously allowed for a malicious (D)TLS server to bypass authentication once knowing which CA’s the client would accept. This also affects mutual authentication cases where the client knows which CA’s the server has loaded. If building with any of these configurations and using (D)TLS where the loaded CA’s could be known and authentication of the peer is desired, users should either: update to the latest wolfSSL version, apply the fix patch, or use the configure flag --disable-openssl-compatible-defaults and not load CA’s with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert() to mitigate the issue.

Why

The product does not validate, or incorrectly validates, a certificate.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Certificate Validation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-295 ↗

CWE-295: Improper Certificate Validation. The product does not validate, or incorrectly validates, a certificate.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCLowVulnerable-system confidentiality: A successful attack can cause a limited loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-295
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-87910Official EUVD mapping

MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification. Affected builds are any that enable the macro WOLFSSL_TRUST_PEER_CERT and load CA certificates with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert(). The peer must know the certificates being loaded to either of those APIs to take advantage of the issue. When OPENSSL_COMPATIBLE_DEFAULTS is also defined this widens the affected API to include all CA certificate loading. Both macros are defined when using autoconf builds such as (nginx, haproxy, stunnel, wpas, apache httpd, hitch, bind, rsyslog, ffmpeg, all, distro). When the certificate is listed as a trusted peer certificate the issue previously allowed for a malicious (D)TLS server to bypass authentication once knowing which CA’s the client would accept. This also affects mutual authentication cases where the client knows which CA’s the server has loaded. If building with any of these configurations and using (D)TLS where the loaded CA’s could be known and authentication of the peer is desired, users should either: update to the latest wolfSSL version, apply the fix patch, or use the configure flag --disable-openssl-compatible-defaults and not load CA’s with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert() to mitigate the issue.

Official EUVD record ↗
JVN iPedia · Japanese · JVNDB-2026-036451wolfSSL Inc.のwolfSSLにおける証明書検証に関する脆弱性

MatchTrustedPeerは使用される公開鍵を無視するため、偽造されたCAクローンが検証を通過してしまいます。影響を受けるビルドは、マクロWOLFSSL_TRUST_PEER_CERTを有効にし、wolfSSL_CTX_trust_peer_cert()またはwolfSSL_trust_peer_cert()でCA証明書を読み込むすべてのものです。この問題を利用するには、ピアがこれらのAPIのいずれかに読み込まれる証明書を知っている必要があります。さらに、OPENSSL_COMPATIBLE_DEFAULTSも定義されている場合、影響範囲はすべてのCA証明書の読み込みに拡大します。これら両方のマクロは、nginx、haproxy、stunnel、wpas、apache httpd、hitch、bind、rsyslog、ffmpegなどのautoconfビルド(およびすべてのディストリビューション)を使用する際に定義されます。証明書が信頼されたピア証明書としてリストされている場合、この問題によりクライアントが受け入れるCAを知っていれば、悪意のある(D)TLSサーバが認証を回避できてしまいます。また、サーバが読み込んだCAをクライアントが知っている相互認証のケースにも影響を与えます。これらの構成でビルドし、かつロードされたCAが既知でピアの認証を行いたい(D)TLSを使用しているユーザーは、最新のwolfSSLバージョンにアップデートするか、修正パッチを適用するか、または--disable-openssl-compatible-defaultsのconfigureフラグを使用し、wolfSSL_CTX_trust_peer_cert()やwolfSSL_trust_peer_cert()でCAを読み込まないようにすることで問題を緩和してください。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
wolfSSL: 5.3.0 ≤ 5.9.2
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 27 Sept 2026 · Last source change 29 Sept 2026, 16:41 UTC · CWE-295 · Improper Certificate Validation

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-27
European sourceENISA EUVD · EUVD-2026-87910
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added patch: github.com/22bcd51d553eaac1de37bee91fdac80cc47961e1; added remediation: github.com/22bcd51d553eaac1de37bee91fdac80cc47961e1.
    Before
    no authoritative guidance recorded
    After
    patch: github.com/22bcd51d553eaac1de37bee91fdac80cc47961e1 · remediation: github.com/22bcd51d553eaac1de37bee91fdac80cc47961e1
    facts@wolfssl.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    wolfSSL: 5.3.0 ≤ 5.9.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    wolfSSL: 5.3.0 ≤ 5.9.2 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    facts@wolfssl.com ↗
  5. ENISA EUVD mappingEUVD-2026-87910 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-87910"}
    ENISA EUVD ↗
  6. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-93302 · cve.blacktree.nl