Wolfssl: >> Wolfssl >> 5.5.0 Security Vulnerabilities
A stack buffer overflow vulnerability exists in wolfSSL's PKCS7 SignedData encoding functionality. In wc_PKCS7_BuildSignedAttributes(), when adding custom signed attributes, the code passes an incorrect capacity value (esd->signedAttribsCount) to EncodeAttributes() instead of the remaining available space in the fixed-size signedAttribs[7] array. When an application sets pkcs7->signedAttribsSz to a value greater than MAX_SIGNED_ATTRIBS_SZ (default 7) minus the number of default attributes already added, EncodeAttributes() writes beyond the array bounds, causing stack memory corruption. In WOLFSSL_SMALL_STACK builds, this becomes heap corruption. Exploitation requires an application that allows untrusted input to control the signedAttribs array size when calling wc_PKCS7_EncodeSignedData() or related signing functions.
CVSS Score
2.2
EPSS Score
0.001
Published
2026-03-19
Integer underflow in wolfSSL packet sniffer <= 5.8.4 allows an attacker to cause a buffer overflow in the AEAD decryption path by injecting a TLS record shorter than the explicit IV plus authentication tag into traffic inspected by ssl_DecodePacket. The underflow wraps a 16-bit length to a large value that is passed to AEAD decryption routines, causing heap buffer overflow and a crash. An unauthenticated attacker can trigger this remotely via malformed TLS Application Data records.
CVSS Score
2.1
EPSS Score
0.003
Published
2026-03-19
In the OpenSSL compatibility layer implementation, the function RAND_poll() was not behaving as expected and leading to the potential for predictable values returned from RAND_bytes() after fork() is called. This can lead to weak or predictable random numbers generated in applications that are both using RAND_bytes() and doing fork() operations. This only affects applications explicitly calling RAND_bytes() after fork() and does not affect any internal TLS operations. Although RAND_bytes() documentation in OpenSSL calls out not being safe for use with fork() without first calling RAND_poll(), an additional code change was also made in wolfSSL to make RAND_bytes() behave similar to OpenSSL after a fork() call without calling RAND_poll(). Now the Hash-DRBG used gets reseeded after detecting running in a new process. If making use of RAND_bytes() and calling fork() we recommend updating to the latest version of wolfSSL. Thanks to Per Allansson from Appgate for the report.
CVSS Score
7.0
EPSS Score
0.004
Published
2025-07-18
The side-channel protected T-Table implementation in wolfSSL up to version 5.6.5 protects against a side-channel attacker with cache-line resolution. In a controlled environment such as Intel SGX, an attacker can gain a per instruction sub-cache-line resolution allowing them to break the cache-line-level protection. For details on the attack refer to: https://doi.org/10.46586/tches.v2024.i1.457-500
CVSS Score
4.1
EPSS Score
0.002
Published
2024-08-29
In function MatchDomainName(), input param str is treated as a NULL terminated string despite being user provided and unchecked. Specifically, the function X509_check_host() takes in a pointer and length to check against, with no requirements that it be NULL terminated. If a caller was attempting to do a name check on a non-NULL terminated buffer, the code would read beyond the bounds of the input array until it found a NULL terminator.This issue affects wolfSSL: through 5.7.0.
CVSS Score
10.0
EPSS Score
0.006
Published
2024-08-27
An issue was discovered in wolfSSL before 5.7.0. A safe-error attack via Rowhammer, namely FAULT+PROBE, leads to ECDSA key disclosure. When WOLFSSL_CHECK_SIG_FAULTS is used in signing operations with private ECC keys,
such as in server-side TLS connections, the connection is halted if any fault occurs. The success rate in a certain amount of connection requests can be processed via an advanced technique for ECDSA key recovery.
CVSS Score
5.1
EPSS Score
0.004
Published
2024-08-27
A malicious TLS1.2 server can force a TLS1.3 client with downgrade capability to use a ciphersuite that it did not agree to and achieve a successful connection. This is because, aside from the extensions, the client was skipping fully parsing the server hello. https://doi.org/10.46586/tches.v2024.i1.457-500
CVSS Score
5.1
EPSS Score
0.005
Published
2024-08-27
Generating the ECDSA nonce k samples a random number r and then
truncates this randomness with a modular reduction mod n where n is the
order of the elliptic curve. Meaning k = r mod n. The division used
during the reduction estimates a factor q_e by dividing the upper two
digits (a digit having e.g. a size of 8 byte) of r by the upper digit of
n and then decrements q_e in a loop until it has the correct size.
Observing the number of times q_e is decremented through a control-flow
revealing side-channel reveals a bias in the most significant bits of
k. Depending on the curve this is either a negligible bias or a
significant bias large enough to reconstruct k with lattice reduction
methods. For SECP160R1, e.g., we find a bias of 15 bits.
CVSS Score
4.1
EPSS Score
0.003
Published
2024-08-27
Remotely executed SEGV and out of bounds read allows malicious packet sender to crash or cause an out of bounds read via sending a malformed packet with the correct length.
CVSS Score
7.5
EPSS Score
0.007
Published
2024-03-25
In wolfSSL prior to 5.6.6, if callback functions are enabled (via the WOLFSSL_CALLBACKS flag), then a malicious TLS client or network attacker can trigger a buffer over-read on the heap of 5 bytes (WOLFSSL_CALLBACKS is only intended for debugging).
CVSS Score
5.3
EPSS Score
0.006
Published
2024-02-20