CVE-2026-74871
openssl_encrypt before 1.4.6 KDF Bypass via Sequential-XOR
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.
INFO
Published Date :
Aug. 17, 2026, 11:16 a.m.
Last Modified :
Sept. 10, 2026, 4:56 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update OpenSSL to version 1.4.6 or later.
- Ensure secure KDF configuration.
- Avoid sequential XOR composition mode if possible.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74871.
| URL | Resource |
|---|---|
| https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-vxf9-vwp6-2w43 | Mitigation Vendor Advisory |
| https://www.vulncheck.com/advisories/openssl-encrypt-before-kdf-bypass-via-sequential-xor | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74871 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74871
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74871 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74871 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:jahlives:openssl_encrypt:*:*:*:*:*:python:*:* versions up to (excluding) 1.4.6 Added Reference Type VulnCheck: https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-vxf9-vwp6-2w43 Types: Mitigation, Vendor Advisory Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/openssl-encrypt-before-kdf-bypass-via-sequential-xor Types: Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-74871', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-17T17:35:23.785880Z'} -
New CVE Received by [email protected]
Aug. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'jahlives', 'product': 'openssl_encrypt', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '1.4.6', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '1.4.6', 'versionType': 'semver'}], 'packageURL': 'pkg:pypi/openssl_encrypt', 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-916 Added Reference https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-vxf9-vwp6-2w43 Added Reference https://www.vulncheck.com/advisories/openssl-encrypt-before-kdf-bypass-via-sequential-xor