CVE-2026-61898: accountsservice: shell injection via attacker-controlled ~/.pam_environment in Ubuntu language helper scripts

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-20 · updated 2026-10-18
Weakness: CWE-78

Description

The Ubuntu-specific language helper scripts (save-to-pam-env, update-langlist) shipped with accountsservice before 23.13.9-8ubuntu7 treat the user-controlled LANGUAGE entry in ~/.pam_environment as trusted input. The value is interpolated unescaped into a GNU sed replacement expression, allowing an attacker to inject a sed 'e' flag and arbitrary shell commands that execute with the privileges of the AccountsService helper process (real UID 0) via the SetLanguage D-Bus method.

Affected products

Canonical accountsservice: from 22.07.5-2ubuntu1 before 22.07.5-2ubuntu1.6; from 23.13.9-2ubuntu6 before 23.13.9-2ubuntu6.1; from 23.13.9-8ubuntu5 before 23.13.9-8ubuntu5.2; from 23.13.9-8ubuntu6 before 23.13.9-8ubuntu7 — fixed in 22.07.5-2ubuntu1.6, 23.13.9-2ubuntu6.1, 23.13.9-8ubuntu5.2, 23.13.9-8ubuntu7

How to fix

Upgrade to a fixed version: Canonical accountsservice 22.07.5-2ubuntu1.6, 23.13.9-2ubuntu6.1, 23.13.9-8ubuntu5.2, 23.13.9-8ubuntu7. Check the vendor advisory for mitigations.

References

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