Memory corruption via unchecked XPath attribute access
Published Apr 29, 2025 · Updated Apr 13, 2026
Out-of-bounds read in XPath parsing in Mozilla Firefox and Thunderbird before 138 allows remote attackers to access process memory. The parser accesses attributes without required null checks, producing undefined behavior that can read beyond allocated bounds and corrupt memory. Processing attacker-controlled XPath input is required; published evidence establishes memory exposure and corruption, but not code execution.
Summary
What happened
Out-of-bounds read in XPath parsing in Mozilla Firefox and Thunderbird before 138 allows remote attackers to access process memory. The parser accesses attributes without required null checks, producing undefined behavior that can read beyond allocated bounds and corrupt memory. Processing attacker-controlled XPath input is required; published evidence establishes memory exposure and corruption, but not code execution.
The record
- CVE
- CVE-2025-4087
- Published
- Apr 29, 2025
- Updated
- Apr 13, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 29, 2025CVE publishedPublication date reported by the CVE source.
- Apr 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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