CVE-2025-1009

9.8 CRITICAL 1% exploit odds Fix listed Memory safety Browser & mail

What it is

An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 1.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-02-04 14:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-05 15:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.2% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-02-04 14:15 UTC
Last modified: 2026-10-05 15:10 UTC
Exploit probability: 1.2% · EPSS, next 30 days
Weakness: CWE-416 · Use after free
Record status: Modified

Affected

Mozilla Firefox < 115.20.0
Mozilla Firefox < 135.0
Mozilla Firefox < 128.7.0
Mozilla Thunderbird < 128.7.0
Mozilla Thunderbird < 135.0

Attack profile CVSS 3.1 · 9.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2025-1009.md and follow it. Check whether this project is affected by CVE-2025-1009. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record