Heap-memory disclosure via undersized LZSS window
Published Mar 19, 2026 · Updated Mar 19, 2026
Heap out-of-bounds read in libarchive on affected Red Hat platforms allows remote attackers to disclose heap data through a crafted RAR archive. After a PPMd block enlarges dictionary_size, parse_codes() reuses an eight-byte LZSS window; copy_from_lzss_window() then reads beyond that allocation before archive_read_data() reports the CRC failure. Exploitation requires an affected system or service to process attacker-supplied RAR3 archives automatically, and the consequence is limited to disclosure of adjacent heap contents.
Summary
What happened
Heap out-of-bounds read in libarchive on affected Red Hat platforms allows remote attackers to disclose heap data through a crafted RAR archive. After a PPMd block enlarges dictionary_size, parse_codes() reuses an eight-byte LZSS window; copy_from_lzss_window() then reads beyond that allocation before archive_read_data() reports the CRC failure. Exploitation requires an affected system or service to process attacker-supplied RAR3 archives automatically, and the consequence is limited to disclosure of adjacent heap contents.
The record
- CVE
- CVE-2026-4424
- Published
- Mar 19, 2026
- Updated
- Mar 19, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 19, 2026CVE publishedPublication date reported by the CVE source.
- Mar 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
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Your stack
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