Bug 2563606 (CVE-2026-118767)

Summary:	CVE-2026-118767 botan: botan: Password policy bypass via embedded null byte in Python bindings
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	jlanda, kshier, rbobbitt, rhel-process-autobot, simaishi, stcannon, watson-tool-maintainers, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Botan. Its Python bindings fail to properly reject embedded null characters when converting strings, causing bcrypt password hashing functions to truncate the input at the null byte. A remote attacker can exploit this flaw to bypass password length and complexity policies, as an application may validate a full password string while only the prefix before the null byte is hashed and checked.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2568564, 2568565, 2568566, 2568567
Bug Blocks:

Description OSIDB Bzimport 2026-10-29 18:13:29 UTC

Botan is a C++ cryptography library. From 1.11.22 until 3.13.0, Botan's Python binding converted Python strings containing U+0000 to const char* values without consistently rejecting the embedded NUL, causing bcrypt and check_bcrypt to process only the prefix before the NUL. Applications could validate a longer password but hash a shorter effective value, allowing application password-policy bypass; scrypt and argon2 are unaffected. This issue is fixed in version 3.13.0.