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CVE-2026-107496— Infinite Loop in CMS_encrypt() With an EC Group Order of 1

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：当尝试将 CMS 消息加密至一个群阶（group order）为 1 的椭圆曲线（EC）证书时，或函数可能会陷入无限循环。影响摘要：能够向执行 CMS 加密的应用程序提供接收方证书的攻击者，可导致该应用程序无限循环，从而耗尽 CPU 资源并引发拒绝服务（DoS）攻击。 CWE 编号：CWE-835：存在不可达退出条件的循环（“无限循环”）详细描述：和函数会将消息加密至一个或多个接收方证书；对于椭圆曲线（EC）接收方，该函数会在接收方的椭圆曲线群中生成一个临时密钥。如果证书声明的群阶为 1，

AI Predicted 5.5 Difficulty: Moderate Updated Nov 11, 2026

Affected Version Matrix 6

Vendor	Product	Version Range	Status
OpenSSL	OpenSSL	`4.1.0< 4.1.1`	affected
		`4.0.0< 4.0.4`	affected
		`3.5.0< 3.5.10`	affected
		`3.0.0< 3.0.24`	affected
		`1.1.1< 1.1.1zk`	affected
		`1.0.2< 1.0.2zt`	affected

Updated Nov 11, 2026

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Vulnerability Information

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Vulnerability Title

Infinite Loop in CMS_encrypt() With an EC Group Order of 1

Source: CVE Program / CVE List V5

Vulnerability Description

Issue summary: Encrypting a CMS message to an EC certificate whose group order is 1 may cause CMS_encrypt() or CMS_encrypt_ex() to loop indefinitely. Impact summary: An attacker able to supply the recipient certificate to an application performing CMS encryption can cause that application to loop indefinitely, consuming CPU and resulting in Denial of Service. CWE: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') Description: CMS_encrypt() and CMS_encrypt_ex() encrypt a message to one or more recipient certificates and, for an EC recipient, generate an ephemeral key in the recipient's group. If the certificate declares a group order of 1, random scalar generation can only produce zero. The key generation routine then retries without limit while waiting for a nonzero private scalar, so the call never returns. The OpenSSL TLS and QUIC implementations do not use this path. An application is exposed only if it calls CMS_encrypt() or CMS_encrypt_ex() with a recipient certificate whose EC parameters are attacker-controlled. Certificates with normal EC group orders do not trigger the loop. OpenSSL 4.0 and later reject unknown explicit EC groups in default builds. These versions are affected only when configured with the enable-ec_explicit_curves option. The result is a hang that consumes a CPU core until the process is interrupted, a Denial of Service. The severity is Low because the attacker must supply the recipient certificate and the application must choose to encrypt to it; ordinary CMS encryption to trusted recipients is unaffected. The fix makes EC key generation fail when the group has no valid nonzero private scalar, instead of retrying indefinitely. FIPS impact: no The FIPS modules in 4.1, 4.0, 3.5 and 3.0 are not affected. The FIPS provider does not support arbitrary explicit EC domain parameters, so an order-1 group is rejected during key import before the vulnerable key generation path is reached.

Source: CVE Program / CVE List V5

CVSS Information

N/A

Source: CVE Program / CVE List V5

Vulnerability Type

不可达退出条件的循环(无限循环)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
OpenSSL	OpenSSL	4.1.0 ~ 4.1.1	-

II. Public POCs for CVE-2026-107496

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-107496

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Vendor Advisories for CVE-2026-107496 (1)

🔗 https://openssl-library.org/news/secadv/20261110.txt vendor-advisory

Other References for CVE-2026-107496 (3)

https://www.cve.org/CVERecord?id=CVE-2026-107496

Same Patch Batch · OpenSSL · 2026-11-10 · 5 CVEs total

CVE-2026-95691		Retransmitted QUIC CRYPTO Frames Can Cause DoS or One-byte Disclosure
CVE-2026-95692		Out-of-Bounds Read and Incorrect IV Length Handling in AES-GCM-SIV
CVE-2026-88823		AES-GCM-SIV AAD Forgery After Zero-length Incremental AAD Update
CVE-2026-88822		QUIC Uses Uninitialized Stack Bytes During Automated Peer Detection

IV. Related Vulnerabilities

Same product: OpenSSL

Same vendor: OpenSSL

Same weakness: CWE-835