CVE-2026-35188
MediumCVSS 5.0Exploitation Probability (EPSS)
Low risk16th percentile - higher than 16% of all known CVEs
Summary
OpenSSL is vulnerable to a double-free in the client certificate verification path when OCSP stapling is used. A malicious server can trigger heap memory corruption via a crafted OCSP response.
Risk Assessment
This vulnerability can lead to denial of service or potentially arbitrary code execution, depending on the environment.
Recommendation
Update OpenSSL to a patched version. If OCSP stapling is not required, consider disabling it.
Other vulnerabilities in OpenSSL
See all- CVE-2016-8610High
A denial of service flaw was found in OpenSSL 0.9.8, 1.0.1, 1.0.2 through 1.0.2h, and 1.1.0 in the way the TLS/SSL protocol defined processing of ALERT packets during a connection handshake. A remote attacker could use this flaw to make a TLS/SSL server consume an excessive amount of CPU and fail to accept connections from other clients.
- CVE-2017-3731High
CVE-2017-3731 affects SSL/TLS servers and clients running on 32-bit hosts that may crash due to an out-of-bounds read caused by a truncated packet. For OpenSSL 1.1.0, the crash can be triggered using the CHACHA20/POLY1305 cipher, and for OpenSSL 1.0.2 using RC4-MD5.
- CVE-2017-3730High
In OpenSSL 1.1.0 before 1.1.0d, a malicious server can supply bad parameters for a DHE or ECDHE key exchange, leading to the client attempting to dereference a NULL pointer, resulting in a client crash.
- CVE-2016-7054High
In OpenSSL 1.1.0 before 1.1.0c, TLS connections using *-CHACHA20-POLY1305 ciphersuites are susceptible to a DoS attack by corrupting larger payloads. This can result in an OpenSSL crash.
- CVE-2016-7052High
OpenSSL 1.0.2i has a vulnerability that allows remote attackers to cause application crashes by triggering a CRL operation, leading to a NULL pointer dereference.
- CVE-2016-6305High
The ssl3_read_bytes function in OpenSSL 1.1.0 before version 1.1.0a allows remote attackers to cause a denial of service (infinite loop) by triggering a zero-length record in an SSL_peek call.
- CVE-2016-6304High
Multiple memory leaks in t1_lib.c in OpenSSL before 1.0.1u, 1.0.2 before 1.0.2i, and 1.1.0 before 1.1.0a allow remote attackers to cause a denial of service (memory consumption) via large OCSP Status Request extensions.
- CVE-2016-6302High
The tls_decrypt_ticket function in OpenSSL before 1.1.0 does not consider the HMAC size during validation of the ticket length, allowing remote attackers to cause a denial of service via a ticket that is too short.
- CVE-2016-2179High
The DTLS implementation in OpenSSL before 1.1.0 does not properly restrict the lifetime of queue entries associated with unused out-of-order messages. This allows remote attackers to cause a denial of service (memory consumption) by maintaining many crafted DTLS sessions simultaneously.
- CVE-2016-2176High
The X509_NAME_oneline function in OpenSSL before 1.0.1t and 1.0.2 before 1.0.2h allows remote attackers to obtain sensitive information from process stack memory or cause a denial of service (buffer over-read) via crafted EBCDIC ASN.1 data.
Original NVD description (English source)
Issue summary: A malicious server can exploit TLS OCSP stapling by delivering a crafted response through the status_request extension, triggering a double-free in the client's certificate verification path. Impact summary: Successful exploitation allows an attacker to corrupt heap memory via a double-free, potentially leading to a Denial of Service or possibly an attacker controlled code execution or other undefined behavior. If OCSP stapling is enabled and the TLS client connects to a malicious server, a crafted OCSP stapled response can trigger a double free in the TLS client when the stapled response is checked. The OCSP stapling is not enabled by default. Reliable code execution through a double-free is technically complex and highly environment-dependent but the Denial of Service impact is straightforward to achieve, warranting Moderate severity. No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.