CVE-2026-91995: pig before 4.1.0 Unverified Password Change via /register/password

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-15 · updated 2026-09-24
Weakness: CWE-620

Description

pig before 4.1.0 contains an authentication bypass vulnerability in the /register/password endpoint where password verification results are discarded, allowing any value as the current password. Remote attackers can submit a username with an incorrect current password to overwrite any account credential including the admin account and gain full administrative control.

Affected products

pig-mesh pig: before 4.1.0 — fixed in 4.1.0

How to fix

Upgrade to a fixed version: pig-mesh pig 4.1.0. Check the vendor advisory for mitigations.

References

https://github.com/geo-chen/oss/blob/main/pig.md
https://github.com/pig-mesh/pig
https://github.com/pig-mesh/pig/blob/v4.0.0/pig-upms/pig-upms-biz/src/main/java/com/pig4cloud/pig/admin/controller/SysRegisterController.java#L21-L53
https://github.com/pig-mesh/pig/blob/v4.0.0/pig-upms/pig-upms-biz/src/main/java/com/pig4cloud/pig/admin/service/impl/SysUserServiceImpl.java#L650-L669
https://github.com/pig-mesh/pig/commit/ce958668f399110b97b3f1fcc5f517ff9bcfd535
https://github.com/pig-mesh/pig/issues/1249
https://www.vulncheck.com/advisories/pig-before-4.1.0-unverified-password-change-via-register-password

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