Detections
Analytics
Linux Distros Unpatched Vulnerability : CVE-2025-66199
medium Nessus Plugin ID 296771
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Synopsis
The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.Description
The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.- Issue summary: A TLS 1.3 connection using certificate compression can be forced to allocate a large buffer before decompression without checking against the configured certificate size limit. Impact summary: An attacker can cause per-connection memory allocations of up to approximately 22 MiB and extra CPU work, potentially leading to service degradation or resource exhaustion (Denial of Service). In affected configurations, the peer-supplied uncompressed certificate length from a CompressedCertificate message is used to grow a heap buffer prior to decompression. This length is not bounded by the max_cert_list setting, which otherwise constrains certificate message sizes. An attacker can exploit this to cause large per-connection allocations followed by handshake failure. No memory corruption or information disclosure occurs. This issue only affects builds where TLS 1.3 certificate compression is compiled in (i.e., not OPENSSL_NO_COMP_ALG) and at least one compression algorithm (brotli, zlib, or zstd) is available, and where the compression extension is negotiated. Both clients receiving a server CompressedCertificate and servers in mutual TLS scenarios receiving a client CompressedCertificate are affected. Servers that do not request client certificates are not vulnerable to client-initiated attacks. Users can mitigate this issue by setting SSL_OP_NO_RX_CERTIFICATE_COMPRESSION to disable receiving compressed certificates. The FIPS modules in 3.6, 3.5, 3.4 and 3.3 are not affected by this issue, as the TLS implementation is outside the OpenSSL FIPS module boundary. OpenSSL 3.6, 3.5, 3.4 and 3.3 are vulnerable to this issue. OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue. (CVE-2025-66199)
Note that Nessus relies on the presence of the package as reported by the vendor.
Solution
There is no known solution at this time.See Also
Plugin Details
Severity: Medium
ID: 296771
File Name: unpatched_CVE_2025_66199.nasl
Version: 1.7
Type: local
Agent: unix
Family: Misc.
Published: 1/27/2026
Updated: 2/1/2026
Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 4.4
CVSS v2
Risk Factor: Medium
Base Score: 4.3
Temporal Score: 3.7
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P
CVSS Score Source: CVE-2025-66199
CVSS v3
Risk Factor: Medium
Base Score: 5.9
Temporal Score: 5.4
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C
Vulnerability Information
CPE: p-cpe:/a:centos:centos:openssl, p-cpe:/a:redhat:enterprise_linux:mokutil, p-cpe:/a:redhat:enterprise_linux:openssl-devel, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:centos:centos:edk2-tools-doc, p-cpe:/a:centos:centos:ovmf, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:redhat:enterprise_linux:mingw64-openssl, p-cpe:/a:redhat:enterprise_linux:edk2-tools, p-cpe:/a:redhat:enterprise_linux:shim-unsigned-x64, p-cpe:/a:centos:centos:compat-openssl10, p-cpe:/a:redhat:enterprise_linux:openssl-perl, p-cpe:/a:centos:centos:aavmf, p-cpe:/a:centos:centos:openssl-libs, p-cpe:/a:centos:centos:openssl-perl, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:redhat:enterprise_linux:openssl-static, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:edk2-tools-doc, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:redhat:enterprise_linux:aavmf, p-cpe:/a:centos:centos:shim-unsigned-x64, p-cpe:/a:centos:centos:openssl-static, cpe:/o:centos:centos:8, p-cpe:/a:canonical:ubuntu_linux:nodejs, p-cpe:/a:centos:centos:edk2, p-cpe:/a:redhat:enterprise_linux:shim-ia32, p-cpe:/a:centos:centos:edk2-ovmf, p-cpe:/a:redhat:enterprise_linux:compat-openssl10, p-cpe:/a:redhat:enterprise_linux:compat-openssl11, p-cpe:/a:redhat:enterprise_linux:edk2, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:openssl-libs, p-cpe:/a:redhat:enterprise_linux:shim-x64, p-cpe:/a:centos:centos:shim-x64, p-cpe:/a:centos:centos:mokutil, p-cpe:/a:centos:centos:mingw64-openssl, p-cpe:/a:redhat:enterprise_linux:shim-unsigned-aarch64, p-cpe:/a:centos:centos:openssl-devel, p-cpe:/a:canonical:ubuntu_linux:edk2, p-cpe:/a:centos:centos:shim-ia32, p-cpe:/a:redhat:enterprise_linux:shim-aa64, p-cpe:/a:redhat:enterprise_linux:mingw32-openssl, cpe:/o:centos:centos:7, p-cpe:/a:centos:centos:compat-openssl11, p-cpe:/a:centos:centos:shim-aa64, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:centos:centos:edk2-tools, p-cpe:/a:redhat:enterprise_linux:edk2-ovmf, p-cpe:/a:centos:centos:mingw32-openssl, p-cpe:/a:redhat:enterprise_linux:shim, p-cpe:/a:redhat:enterprise_linux:openssl, p-cpe:/a:centos:centos:shim-unsigned-aarch64, p-cpe:/a:redhat:enterprise_linux:ovmf, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:centos:centos:edk2-aarch64, p-cpe:/a:centos:centos:shim, p-cpe:/a:redhat:enterprise_linux:edk2-aarch64
Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier
Exploit Ease: No known exploits are available
Reference Information
CVE: CVE-2025-66199