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CVE-2025-4087Unsafe attribute access during XPath parsing
- 4.8MediumCVSS base score
- 0.32%Exploitation in 30 daysEPSS · top 74% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.
Timeline
ID reserved
By mozilla
Published
- 12 months later
· 12 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium4.8 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium4.8 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.32% · top 74% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.8.
Affected products
- unaffected 128.10 – ≤ 128.*
- unaffected 138 – ≤ *
- unaffected 128.10 – ≤ 128.*
- unaffected 138 – ≤ *
References
References6
- https://bugzilla.mozilla.org/show_bug.cgi?id=1952465 (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-28/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-29/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-31/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-32/ (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-12657 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-4087)Record last updated .