Issue summary: The OpenSSL Certificate Management Protocol (CMP) caches additional certificates (extraCerts) sent in a CMP message, but never expunges them (for instance if they are invalid). If a server reuses an OSSL_CMP_CTX frequently, this cache of extraCerts may grow unboundedly, and a malicious client may flood a CMP server with requests driving this growth.
Impact summary: Users utilizing a CMP server that reuses a single OSSL_CMP_CTX for the lifetime of a server process may observe unbounded memory growth in the event a malicious client repeatedly sends requests containing unique extra certificates, which may lead to OOM conditions.
CWE: CWE-770: Allocation of Resources Without Limits or Throttling
Description: If a remote user sends CMP messages to a server with a list of extraCerts and the message is rejected, the extraCerts from the message remains in the server contexts untrusted certificate stack. This exposes servers with long lived ctx objects to Denial of Service attacks in which an attacker sends messages intending to be rejected with a large list of additional certificates repeatedly, forcing the server to store them indefinitely. The issue was fixed by removing the added extra certs if the message is rejected, using the same method as when the context is configured to not do caching at all.
FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade openssl-libsUpgrade openssl-perlUpgrade opensslUpgrade openssl-devel | Oct 11, 2026 | Sep 14, 2026 |
| Alpine Linux | — | Upgrade openssl | Aug 26, 2026 | Aug 25, 2026 |
| Amazon_linux_2023 | — | Upgrade openssl-develUpgrade opensslUpgrade openssl-debugsourceUpgrade openssl-debuginfoUpgrade openssl-snapsafe-libs-debuginfoUpgrade openssl-fips-provider-latestUpgrade openssl-libsUpgrade openssl-fips-provider-latest-debuginfoUpgrade openssl-libs-debuginfoUpgrade openssl-snapsafe-libsUpgrade openssl-perl | Sep 30, 2026 | Aug 25, 2026 |
| Debian | — | Upgrade openssl | Aug 26, 2026 | Aug 25, 2026 |
| Freebsd | — | Upgrade openssl35Upgrade openssl40Upgrade FreeBSDUpgrade openssl36Upgrade openssl34Upgrade openssl | Aug 26, 2026 | Aug 25, 2026 |
| Http Openssl | — | Upgrade to the latest version of OpenSSL | Aug 27, 2026 | Aug 25, 2026 |
| Redhat_linux | — | Upgrade openssl-debuginfoUpgrade openssl-debugsourceUpgrade opensslUpgrade openssl-libs-debuginfoUpgrade openssl-develNo solution existsUpgrade openssl-perlUpgrade openssl-libs | Aug 27, 2026 | Aug 25, 2026 |
| Rocky_linux | — | Upgrade openssl-libs-debuginfoUpgrade openssl-debugsourceUpgrade opensslUpgrade openssl-perlUpgrade openssl-develUpgrade openssl-debuginfoUpgrade openssl-libs | Sep 17, 2026 | Sep 15, 2026 |
| Ubuntu | — | Upgrade libssl3t64Upgrade opensslUpgrade libssl3 | Aug 26, 2026 | Aug 25, 2026 |
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