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CVE-2026-63074— CMP Indefinite Cache Growth of ExtraCerts

Quick assessment

Affected
OpenSSL OpenSSL
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

问题摘要：OpenSSL 证书管理协议（CMP）会缓存 CMP 消息中发送的附加证书（extraCerts），但从未将其清除（例如，即使这些证书无效）。如果服务器频繁重用同一个 上下文，这个 extraCerts 缓存可能会无限制增长，恶意客户端可能通过向 CMP 服务器发送大量请求来驱动这种增长。 影响摘要：对于在其服务器进程生命周期内重用单个 的 CMP 服务器用户，如果恶意客户端反复发送包含不同附加证书的请求，可能会导致内存无限增长，进而引发内存不足（OOM）状况。 CWE：CWE-770：未限制或未限速地分

AI Predicted 7.5 Difficulty: Easy

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 5

VendorProduct Version RangeStatus
OpenSSL OpenSSL 4.0.0< 4.0.2 affected
3.6.0< 3.6.4 affected
3.5.0< 3.5.8 affected
3.4.0< 3.4.7 affected
3.0.0< 3.0.22 affected
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I. Basic Information for CVE-2026-63074

Vulnerability Information
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Vulnerability Title
CMP Indefinite Cache Growth of ExtraCerts
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
OpenSSL OpenSSL 4.0.0 ~ 4.0.2 -

II. Public POCs for CVE-2026-63074

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III. Intelligence Information for CVE-2026-63074

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Patches & Fixes for CVE-2026-63074 (5)

Vendor Advisories for CVE-2026-63074 (1)

Same Patch Batch · OpenSSL · 2026-08-25 · 9 CVEs total

CVE-2026-75803 AEAD Forgeries with Empty Ciphertext When Using EVP_Cipher()
CVE-2026-18798 QUIC Server May Trigger Double Free When Processing INITIAL Packet
CVE-2026-54874 Excessive Memory Use Buffering DTLS Records for a Future Epoch
CVE-2026-63072 Heap Buffer Overflow in CMS Key Unwrapping
CVE-2026-63073 Untrusted Sender DN Used as Format String in CMP Response Validation
CVE-2026-63075 QUIC ACK-only Packet Retention Can Cause Memory Exhaustion
CVE-2026-63076 Invalid Pointer Dereference in CMP Server via Crafted protectionAlg
CVE-2026-14457 RPK Server Signature Algorithm Selection Can Dereference a Missing Certificate

IV. Related Vulnerabilities

Same product: OpenSSL
Same vendor: OpenSSL
Same weakness: CWE-770

V. Comments for CVE-2026-63074

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