CVE-2026-42789
Improper Certificate Validation: Is CVE-2026-42789 real, exploitable, or a false positive? Here's the community verdict.
signals
public sources
Moderate signals. Triage by your actual exposure and reachability.
baseline read
auto · not a community verdict
Low signal — verdict needed
Few public signals point to active risk. Whether a scanner hit here is a true or false positive depends on your version and config — community verdicts decide.
Based on CVSS · FIRST EPSS
Confirm or dispute →CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Improper Following of a Certificate's Chain of Trust vulnerability in Erlang OTP public_key (pubkey_cert module) allows a non-CA certificate to be accepted as an intermediate issuer, enabling certificate chain forgery. In lib/public_key/src/pubkey_cert.erl, pubkey_cert:validate_extensions/7 contains two flaws that together allow a certificate with basicConstraints cA:false and no keyUsage extension to be used as an intermediate issuer in a chain passed to public_key:pkix_path_validation/3: the cA:false clause recurses into the remaining extensions without rejecting the certificate when it is in issuer position, and the keyUsage check only fires when the extension is present, so a certificate lacking keyUsage entirely bypasses the keyCertSign enforcement. Any party holding an end-entity certificate with basicConstraints cA:false and no keyUsage extension, issued by any CA in the victim's trust store, can use that certificate's private key to sign forged leaf certificates for arbitrary identities. public_key:pkix_path_validation/3 accepts the resulting chain, and by extension every TLS or mTLS endpoint built on the OTP ssl application that relies on the default verifier is affected, including server identity verification on the client side and client certificate verification on mTLS servers. This issue affects OTP from OTP 17.0 before OTP 29.0.1, OTP 28.5.0.1, OTP 27.3.4.12 and OTP 26.2.5.21, corresponding to public_key from 0.22 before 1.21.1, 1.20.3.1, 1.17.1.3 and 1.15.1.7.
References
Published
Embed this verdict
[](https://www.truepositive.app/cve/CVE-2026-42789)<a href="https://www.truepositive.app/cve/CVE-2026-42789"><img src="https://www.truepositive.app/cve/CVE-2026-42789/badge.svg" alt="TruePositive verdict for CVE-2026-42789"></a>Live badge that updates automatically as the community verdict changes.
Community ground truth
Be the first practitioner to weigh in
So far this is only TruePositive's editorial baseline from public sources. Add your real-world verdict below — it becomes the signal the next person triaging this relies on.
🥇 The first 50 practitioners to contribute earn a Founding Contributor badge.
In your experience, is this finding real and exploitable?
awaiting field verdictsCurated baseline: A curated baseline from public sources, shown separately from community verdicts.
No account needed. Anonymous verdicts post as an unverified signal. Log in to make yours verified and earn reputation.
Field notes & remediation
Verdicts are the quick signal. Notes are the evidence and fixes behind them.
- 0
No confirmed in-the-wild exploitation or public exploit was found for this yet.
Add a field note or remediationoptional
Related CVEs
Same weakness: CWE-295 · Improper Certificate Validation.
- CVE-2020-0601HIGH 8.1KEVEPSS 89%
A spoofing vulnerability exists in the way Windows CryptoAPI (Crypt32.dll) validates Elliptic Curve Cryptography (ECC) certificates.An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source, aka 'Windows CryptoAPI Spoofing Vulnerability'.
- CVE-2022-26923HIGH 8.8KEVEPSS 83%
Active Directory Domain Services Elevation of Privilege Vulnerability
- CVE-2026-16107MED 5.9
IBM TS4500 CLI tool Versions: 0.1.31 through 1.12.0.0 does not validate or improperly validates TLS certificate validation, which could allow an attacker to obtain sensitive information using man in the middle techniques.
- CVE-2026-50302MED 4.2
Improper certificate validation in Windows Cryptographic Services allows an unauthorized attacker to bypass a security feature over a network.
- CVE-2026-50752HIGH 7.4Real · low riskEPSS 5%
A weakness in the certificate validation logic of the deprecated IKEv1 key exchange may allow an unauthenticated attacker positioned as a man-in-the-middle to bypass certificate validation in VPN site-to-site connections that use certificate-based authentication. Successful exploitation could allow interception or modification of traffic traversing the VPN tunnel.
- CVE-2022-47758CRIT 9.8Real · low riskEPSS 1%
Nanoleaf firmware v7.1.1 and below is missing TLS verification, allowing attackers to execute arbitrary code via a DNS hijacking attack.