Unsafe attribute access during XPath parsing

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Summary

CVECVE-2025-4087
StatePUBLISHED
Assignermozilla
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-04-29 14:15:35 UTC
Updated2026-04-13 15:17:00 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 4.8 MEDIUM from ADP

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

EPSS: 0.004360000 probability, percentile 0.630560000 (date 2026-04-15)

Problem Types: CWE-125 | CWE-125 CWE-125 Out-of-bounds Read

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED4.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary4.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Mozilla Firefox All All All All
Application Mozilla Firefox All All All All
Application Mozilla Thunderbird All All All All
Application Mozilla Thunderbird All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mozilla Firefox unaffected 128.10 128.* rpm Not specified
CNA Mozilla Firefox unaffected 138 * rpm Not specified
CNA Mozilla Thunderbird unaffected 128.10 128.* rpm Not specified
CNA Mozilla Thunderbird unaffected 138 * rpm Not specified

References

ReferenceSourceLinkTags
lists.debian.org/debian-lts-announce/2025/05/msg00024.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
bugzilla.mozilla.org/show_bug.cgi [email protected] bugzilla.mozilla.org Permissions Required
www.mozilla.org/security/advisories/mfsa2025-32 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-31 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-28 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-29 [email protected] www.mozilla.org Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Ivan Fratric (en)

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