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CVE-2025-66199

CVE-2025-66199 · TLS 1.3 CompressedCertificate excessive memory allocation

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 5.9 · Medium · EPSS 0.5% · Fix available

Published
Updated

Stack: system · network

Affected products and versions

  • openssl

    Versions
    • ≥ 3.6.0, < 3.6.1: Affected (semver)
    • ≥ 3.5.0, < 3.5.5: Affected (semver)
    • ≥ 3.4.0, < 3.4.4: Affected (semver)
    • ≥ 3.3.0, < 3.3.6: Affected (semver)

    Update to 3.3.6; Update to 3.4.4; Update to 3.5.5; Update to 3.6.1

  • openssl Debian:13

    Versions
    • 3.5.1-1
    • 3.5.1-1+deb13u1
    • 3.5.2-1
    • 3.5.3-1
    • 3.5.4-1~deb13u1
    Affected ranges
    • ECOSYSTEM: < 3.5.4-1~deb13u2

    Update to 3.5.4-1~deb13u2

  • openssl Debian:14

    Versions
    • 3.5.1-1
    • 3.5.2-1
    • 3.5.3-1
    • 3.5.4-1
    • 3.5.4-1~deb13u1
    • 3.5.4-1~deb13u2
    • 3.5.5-1~deb13u1
    • 3.5.5-1~deb13u2
    Affected ranges
    • ECOSYSTEM: < 3.5.5-1

    Update to 3.5.5-1

  • nodejs Ubuntu:Pro:16.04:LTS

    Versions
    • 0.10.25~dfsg2-2ubuntu1
    • 4.2.2~dfsg-1
    • 4.2.3~dfsg-1
    • 4.2.4~dfsg-1ubuntu1
    • 4.2.4~dfsg-2
    • 4.2.6~dfsg-1ubuntu1
    • 4.2.6~dfsg-1ubuntu4
    • 4.2.6~dfsg-1ubuntu4.1
    • 4.2.6~dfsg-1ubuntu4.2
    • 4.2.6~dfsg-1ubuntu4.2+esm1
    • 4.2.6~dfsg-1ubuntu4.2+esm2
    • 4.2.6~dfsg-1ubuntu4.2+esm3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nodejs Ubuntu:Pro:18.04:LTS

    Versions
    • 6.11.4~dfsg-1ubuntu1
    • 6.11.4~dfsg-1ubuntu2
    • 6.12.0~dfsg-1ubuntu1
    • 6.12.0~dfsg-2ubuntu1
    • 6.12.0~dfsg-2ubuntu2
    • 8.10.0~dfsg-2
    • 8.10.0~dfsg-2ubuntu0.2
    • 8.10.0~dfsg-2ubuntu0.3
    • 8.10.0~dfsg-2ubuntu0.4
    • 8.10.0~dfsg-2ubuntu0.4+esm1
    • 8.10.0~dfsg-2ubuntu0.4+esm2
    • 8.10.0~dfsg-2ubuntu0.4+esm3
    • 8.10.0~dfsg-2ubuntu0.4+esm4
    • 8.10.0~dfsg-2ubuntu0.4+esm5
    • 8.10.0~dfsg-2ubuntu0.4+esm6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nodejs Ubuntu:Pro:22.04:LTS

    Versions
    • 12.22.5~dfsg-5ubuntu1
    • 12.22.7~dfsg-2ubuntu1
    • 12.22.7~dfsg-2ubuntu3
    • 12.22.9~dfsg-1ubuntu2
    • 12.22.9~dfsg-1ubuntu3
    • 12.22.9~dfsg-1ubuntu3.1
    • 12.22.9~dfsg-1ubuntu3.2
    • 12.22.9~dfsg-1ubuntu3.3
    • 12.22.9~dfsg-1ubuntu3.4
    • 12.22.9~dfsg-1ubuntu3.5
    • 12.22.9~dfsg-1ubuntu3.6
    • 12.22.9~dfsg-1ubuntu3.6+esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • edk2 Ubuntu:24.04:LTS

    Versions
    • 2023.05-2
    • 2023.11-2
    • 2023.11-3
    • 2023.11-4
    • 2023.11-5
    • 2023.11-6
    • 2023.11-8
    • 2024.02-1
    • 2024.02-2
    • 2024.02-2ubuntu0.1
    • 2024.02-2ubuntu0.3
    • 2024.02-2ubuntu0.4
    • 2024.02-2ubuntu0.5
    • 2024.02-2ubuntu0.6
    • 2024.02-2ubuntu0.7
    • 2024.02-2ubuntu0.8
    • 2024.02-2ubuntu0.9
    • 2024.02-2ubuntu0.10
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • edk2 Ubuntu:25.10

    Versions
    • 2025.02-3ubuntu2
    • 2025.02-8
    • 2025.02-8ubuntu1
    • 2025.02-8ubuntu2
    • 2025.02-8ubuntu3
    • 2025.02-8ubuntu3.1
    • 2025.02-8ubuntu3.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • openssl Ubuntu:25.10

    Versions
    • 3.4.1-1ubuntu3
    • 3.5.0-2ubuntu1
    • 3.5.2-1ubuntu1
    • 3.5.3-1ubuntu2
    Affected ranges
    • ECOSYSTEM: < 3.5.3-1ubuntu3

    Update to 3.5.3-1ubuntu3

  • edk2 Ubuntu:26.10

    Versions
    • 2025.11-3ubuntu7
    • 2025.11-3ubuntu8
    • 2026.05-2ubuntu1
    • 2026.05-2ubuntu2
    • 2026.05-2ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • edk2-hwe Ubuntu:26.10

    Versions
    • 2025.11-3ubuntu8
    • 2025.11-3ubuntu9
    • 2026.05-2ubuntu1
    • 2026.05-2ubuntu2
    • 2026.05-2ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • edk2 Ubuntu:26.04:LTS

    Versions
    • 2025.02-8ubuntu3
    • 2025.11-3ubuntu6
    • 2025.11-3ubuntu7
    • 2025.11-3ubuntu7.2
    • 2025.11-3ubuntu7.3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • edk2-hwe Ubuntu:26.04:LTS

    Versions
    • 2025.11-3ubuntu6
    • 2025.11-3ubuntu8
    • 2025.11-3ubuntu8.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • openssl Ubuntu:26.04:LTS

    Versions
    • 3.5.3-1ubuntu2
    Affected ranges
    • ECOSYSTEM: < 3.5.5-1ubuntu1

    Update to 3.5.5-1ubuntu1

Original sources

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