---
schema_version: '1.0'
id: security-20260705-2dcafc
url: https://osv.dev/vulnerability/DEBIAN-CVE-2025-66199
url_hash: 2dcafc11a6bd2f3d8b6b70e436e7595e6d479b21d9e9f9f3272fc0ef0661b501
canonical_url: https://osv.dev/vulnerability/DEBIAN-CVE-2025-66199
source: osv:debian
category: security/os
category_raw: cve/os
region: null
tags:
- cve
- DEBIAN-CVE-2025-66199
- severity:CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- openssl
- Debian
lang: en
published_at: '2026-01-27T16:16:15Z'
fetched_at: '2026-07-05T15:34:34Z'
updated_at: '2026-07-05T15:35:57Z'
status: published
content_hash: d7925e5987b5d1142dceacc5506f9529c9baf3232372f3dc5f7c0d3b4f09786b
license_note: full
summary: '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 approx'
summary_source: rss
summary_en: '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 approx'
entities: []
key_facts: []
related: []
related_auto: []
title: DEBIAN-CVE-2025-66199 — openssl
---

# DEBIAN-CVE-2025-66199 — openssl

## TL;DR
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 approx

## Key Points
- cve / DEBIAN-CVE-2025-66199 / severity:CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H / openssl / Debian

## Details
**Severity:** CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
**Advisory:** DEBIAN-CVE-2025-66199

**Affected (your watchlist):**
- `Debian:openssl` 3.0.11-1~deb12u2 → no fixed version listed [rpi]

**Details:**
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.

**References:**
- https://security-tracker.debian.org/tracker/CVE-2025-66199

_Data: OSV.dev (upstream: debian) — https://osv.dev/vulnerability/DEBIAN-CVE-2025-66199_

## Source
元記事: [DEBIAN-CVE-2025-66199 — openssl](https://osv.dev/vulnerability/DEBIAN-CVE-2025-66199) — published 2026-01-27T16:16:15Z