Memory Allocation with Excessive Size Value Affecting openssl package, versions [3.1.0,3.3.6)[3.4.0,3.4.4)[3.5.0,3.5.5)[3.6.0,3.6.1)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CONAN-OPENSSL-15124052
- published28 Jan 2026
- disclosed27 Jan 2026
- creditTomas Dulka,Stanislav Fort
Introduced: 27 Jan 2026
CVE-2025-66199 (opens in a new tab)How to fix?
Upgrade openssl to version 3.3.6, 3.4.4, 3.5.5, 3.6.1 or higher.
Overview
Affected versions of this package are vulnerable to Memory Allocation with Excessive Size Value. (up to 22 MiB) when allocating buffers for CompressedCertificate messages on a TLS 1.3 connection with certificate compression. An attacker can cause service degradation or resource exhaustion. The certificate length is not bounded by the max_cert_list setting, allowing large allocations and failure.
No memory corruption or information disclosure occurs.
Note: This only affects applications compiled wtih TLS 1.3 certificate compression (not OPENSSL_NO_COMP_ALG), with at least one compression algorithm (brotli, zlib, or zstd) available, and where the compression extension is negotiated.