JLSEC-2026-745 Bleichenbacher padding oracle in PKCS#7 KTRI decryption. When decrypting PKCS#7 EnvelopedData...

Bleichenbacher padding oracle in PKCS7 KTRI decryption. When decrypting PKCS7 EnvelopedData using RSA PKCS1 v1.5 key transport, wolfSSL returned distinguishable error codes depending on whether RSA padding validation failed versus whether the decrypted content was malformed. An attacker able to...

CVE-2026-48747

Summary: CVE-2026-48747 affects Symfony’s Mailomat webhook parser. The MailomatRequestParser::validateSignature() method reads the X-MOM-Webhook-Signature header and passes the wire-provided algorithm directly to hash_hmac(), enabling a signature algorithm downgrade instead of enforcing SHA-256 a...

PYSEC-2026-2528 joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)

Summary joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None. HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/rfc7518/jwsalgs.py:62-70 feed whatever OctKey.getopkey... produced into hmac.new..., and...

joserfc: HS256/HS384/HS512 verify accepts empty/nil HMAC key (cross-language sibling of CVE-2026-45363)

Summary joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None. HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/rfc7518/jwsalgs.py:62-70 feed whatever OctKey.getopkey... produced into hmac.new..., and...

CVE-2026-8720

CVE-2026-8720 affects wolfSSL’s HMAC-BLAKE2 APIs (wc_Blake2bHmacFinal, wc_Blake2sHmacFinal). When the supplied key length exceeds the BLAKE2 block size, the key-hashing branch reinitializes the running hash state and discards accumulated message data, causing the MAC to depend only on the key and...

openssl: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys

A flaw was found in OpenSSL. This vulnerability allows a remote attacker to forge PKCS12 Public-Key Cryptography Standards 12 files that use Password-Based Message Authentication Code 1 PBMAC1 with short HMAC Hash-based Message Authentication Code keys. This can lead to a service accepting...

PYSEC-2026-179

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, when the verifier is decoding JSON Web Tokens, while supporting both asymmetric and HMAC algorithms, the library does not validate use of JSON Web Keys in HMAC algorithm, allowing attacker to use the issuer public key as the...

CVE-2026-41244 Mojic: Observable Timing Discrepancy in HMAC Verification

Mojic is a CLI tool to transform readable C code into an unrecognizable chaotic stream of emojis. Prior to 2.1.4, the CipherEngine uses a standard equality operator !== to verify the HMAC-SHA256 integrity seal during the decryption phase. This creates an Observable Timing Discrepancy CWE-208,...

CVE-2026-40194

A flaw was found in phpseclib, a PHP secure communications library. This vulnerability involves a timing attack where the comparison of Secure Shell SSH packet integrity checks HMACs takes a variable amount of time. A remote attacker could exploit this timing difference to deduce information abou...

GHSA-6GVQ-JCMP-8959 ALTCHA Proof-of-Work Vulnerable to Challenge Splicing and Replay

Impact A cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modifi...

CVE-2025-59058 httpsig-rs's HMAC verification is vulnerable to timing attack

httpsig-rs is a Rust implementation of IETF RFC 9421 http message signatures. Prior to version 0.0.19, the HMAC signature comparison is not timing-safe. This makes anyone who uses HS256 signature verification vulnerable to a timing attack that allows the attacker to forge a signature. Version...

PT-2025-37315

Name of the Vulnerable Software and Affected Versions: httpsig-rs versions prior to 0.0.19 Description: httpsig-rs is a Rust implementation of IETF RFC 9421 http message signatures. The HMAC signature comparison is not timing-safe in versions prior to 0.0.19, potentially allowing an attacker to...

krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions

A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4-HMAC-MD5 to be spoofed due to weaknesses in the MD5 checksum design. If RC4 is preferred over stronger encryption types, an attacker could exploit MD5 collisions to forge message integrity codes. This ma...

A Comparative Study and Implementation of Key Derivation Functions Standardized by NIST and IEEE

Since many applications and services require pseudorandom numbers PRNs, it is feasible to generate specific PRNs under given key values and input messages using Key Derivation Functions KDFs. These KDFs are primarily constructed based on Message Authentication Codes MACs, where the MAC serves as ...

The vulnerability of the gcry_md_get_algo_dlen() function in ClusterLabs Booth’s high-availability cluster management and monitoring software allows a attacker to perform an invalid HMAC.

The vulnerability of the gcrymdgetalgodlen function in ClusterLabs Booth’s high-availability cluster management and monitoring software is related to insufficient verification of data authenticity. Exploiting this vulnerability could allow an attacker operating remotely to generate invalid HMACs...

PT-2024-3101 · 1Panel · 1Panel

Name of the Vulnerable Software and Affected Versions: 1Panel versions prior to 1.10.3-lts Description: The issue is related to the password verification in the source code of 1Panel, which uses the != symbol instead of hmac.Equal. This may lead to a timing attack vulnerability, potentially...

CVE-2023-36400

Windows HMAC Key Derivation Elevation of Privilege Vulnerability...

SUSE CVE-2022-48566

An issue was discovered in comparedigest in Lib/hmac.py in Python through 3.9.1. Constant-time-defeating optimisations were possible in the accumulator variable in hmac.comparedigest...

PT-2023-24897 · Ami · Ami Spx

Name of the Vulnerable Software and Affected Versions: AMI SPx affected versions not specified Description: The issue is related to a missing cryptographic step in the BMC of AMI SPx, where a user can generate a hash-based message authentication code HMAC. This could lead to the loss of...

The vulnerability of the implementation of the HMAC-SHA-384 mechanism in the GnuTLS cryptographic library allows a perpetrator to carry out an “Lucky 13” attack and a attack that recovers the plaintext.

The vulnerability of the implementation of the HMAC-SHA-384 mechanism in the GnuTLS cryptographic library is related to errors in the implementation of the cryptographic algorithm. Exploiting this vulnerability allows a malicious actor to perform both a “Lucky 13” attack and an attack that recove...