What’s Vulnerable › Vulnerabilities

CVE-2025-0238: Use-after-free when breaking lines in text

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-01-07 · updated 2026-10-05
• Weakness: CWE-416

Description

Assuming a controlled failed memory allocation, an attacker could have caused a use-after-free, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Firefox ESR 115.19, Thunderbird 134, and Thunderbird 128.6.

Affected products

• Mozilla Firefox: before 115.19.0; before 134.0; from 116.0 before 128.6.0 — fixed in 115.19.0, 128.6.0, 134.0
• Mozilla Thunderbird: before 128.6; from 129.0 before 134.0 — fixed in 128.6, 134.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 115.19.0, 128.6.0, 134.0; Mozilla Thunderbird 128.6, 134.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1915535
• https://www.mozilla.org/security/advisories/mfsa2025-01/
• https://www.mozilla.org/security/advisories/mfsa2025-02/
• https://www.mozilla.org/security/advisories/mfsa2025-03/
• https://www.mozilla.org/security/advisories/mfsa2025-04/
• https://www.mozilla.org/security/advisories/mfsa2025-05/
• https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html

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