Vulnerability · Published Aug 17, 2026 · Assigned by VulnCheck

CVE-2026-74871openssl_encrypt before 1.4.6 KDF Bypass via Sequential-XOR

Medium 6.2

In plain English

A medium-severity security flaw in openssl_encrypt from jahlives. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.2Medium

Exploit odds (30 days)0.1%top 98.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

openssl_encrypt versions before 1.4.6 contain a key derivation flaw in sequential XOR composition mode where the last stage cancels out during key generation. When configured with a single KDF and no prior hashing stage, attackers can bypass memory-hard key derivation and perform offline password cracking at SHA-256 speed instead of the configured KDF cost.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	openssl-encrypt	1.4.6	PYSEC-2026-3976

Affected products (as reported)

Vendor	Product	Versions
jahlives	openssl_encrypt	0 – before 1.4.6

Weakness: CWE-916 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

GitHub Security Advisory (GHSA-vxf9-vwp6-2w43) vendor-advisory
VulnCheck Advisory: openssl_encrypt before 1.4.6 KDF Bypass via Sequential-XOR third-party-advisory