CVE Watch5 sept 2026

CVE-2026-67278

MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an

CVSS

—

Sin CVSS

EPSS

—

KEV

—

Exploit Today

—

0-100

Publicado: 5 sept 2026 · Última mod.: 5 sept 2026 · CWE-347

EPSS · 30d

Sin historial EPSS suficiente todavía.

Descripción técnica

MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

Referencias oficiales

CVEs relacionados

CVECVSSEPSSKEVRExplotTítuloVis.

CVE-2026-67276—

—

———RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)8h CVE-2026-527678.2 ALT

—

——0YesWiki is a wiki system written in PHP. From version 4.6.2 to before version 4.6.6, HttpSignatureService::verifySignature() checks the result of PHP's openssl_verify() with a loose boolean negation - if (!openssl_verify(...)) { throw ... }. PHP's openssl_verify has four possible return values: 1, 0, -1, and "false". The -1 row is the bypass: PHP's truthiness rules make -1 a truthy value, so !(-1) === false, the throw is skipped, and the controller proceeds to processActivity(). Any condition that makes OpenSSL's EVP_VerifyFinal() return -1 triggers the bypass. The reachable consequence is the controller silently treats a failed verification as success and processes the attacker's payload. This issue has been patched in version 4.6.6.1d CVE-2026-855257.4 ALT

1.2%

——0Improper OCSP response validation in the Snowflake Python, Go, JDBC, and Node.js drivers allowed a revoked TLS certificate to be accepted as valid, because OCSP responses were not reliably bound to the certificate being validated and definitive verification failures were treated as transient. A man-in-the-middle attacker holding a revoked certificate and its private key for a Snowflake or stage hostname could cause the driver to establish a TLS session to the attacker-controlled endpoint anyway, allowing the attacker to read and modify data transmitted within that connection. Successful exploitation requires that on-path position and the corresponding private key, and impact is limited to data carried within the intercepted connection. The fix is available in the patched versions listed above. Users must manually upgrade.1d CVE-2026-800989.3 CRÍ

21.5%

——6Improper verification of cryptographic signature in Copilot Studio allows an unauthorized attacker to elevate privileges over a network.1d CVE-2026-841855.9 MED

0.4%

——0A flaw was found in the jwcrypto library, which is used for implementing Javascript Object Signing and Encryption (JOSE) standards. The issue occurs when the library verifies a General JSON Serialization JWS using a set of keys. Due to a coding error, the library fails to correctly identify the specific key ID (kid) and may instead accept a signature made by any valid key in the set. This can allow an attacker with a valid key to bypass authorization checks in applications that rely on the key ID to identify specific tenants or users.1d CVE-2026-853949.1 CRÍ

12.7%

——4python-jose through 3.5.0 fails to properly validate asymmetric keys in HMAC initialization, accepting DER-encoded public keys that lack PEM armor or SSH prefixes. Attackers holding the service's public key can forge HS256 tokens that pass verification when algorithms are not explicitly restricted. This is an incomplete fix for CVE-2024-33663.2d