Heap out-of-bounds read via empty encoded hash
Published May 13, 2026 · Updated May 13, 2026
Heap out-of-bounds read in Crypt::Argon2 0.017 through 0.030 allows attackers to crash a Perl process via an empty encoded hash. The auto-detect branch in argon2_verify subtracts one from a zero encoded length and passes the wrapped SIZE_MAX value to memchr, which scans beyond the heap buffer for a dollar separator. Reachability requires a caller to supply an empty stored hash; the over-read can terminate the process or expose the position of an adjacent dollar byte to later parsing.
Summary
What happened
Heap out-of-bounds read in Crypt::Argon2 0.017 through 0.030 allows attackers to crash a Perl process via an empty encoded hash. The auto-detect branch in argon2_verify subtracts one from a zero encoded length and passes the wrapped SIZE_MAX value to memchr, which scans beyond the heap buffer for a dollar separator. Reachability requires a caller to supply an empty stored hash; the over-read can terminate the process or expose the position of an adjacent dollar byte to later parsing.
The record
- CVE
- CVE-2026-8463
- Published
- May 13, 2026
- Updated
- May 13, 2026
- Vendor
- Leon Timmermans
- Product
- Crypt::Argon2
- Classifications
- CWE-126, CWE-191, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 13, 2026CVE publishedPublication date reported by the CVE source.
- May 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0.017 <0.031
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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