Memory disclosure via off-by-one AJP getter reads
Published May 4, 2026 · Updated May 4, 2026
Out-of-bounds reads in mod_proxy_ajp in Apache HTTP Server 2.4.66 and earlier allow remote attackers to disclose memory via AJP messages. The AJP message getter functions in modules/proxy/ajp_msg.c apply off-by-one length checks, allowing reads past the message buffer. Exposure requires mod_proxy_ajp to process attacker-controlled AJP data; the published impact is limited to memory disclosure, with no reported write or service interruption.
Summary
What happened
Out-of-bounds reads in mod_proxy_ajp in Apache HTTP Server 2.4.66 and earlier allow remote attackers to disclose memory via AJP messages. The AJP message getter functions in modules/proxy/ajp_msg.c apply off-by-one length checks, allowing reads past the message buffer. Exposure requires mod_proxy_ajp to process attacker-controlled AJP data; the published impact is limited to memory disclosure, with no reported write or service interruption.
The record
- CVE
- CVE-2026-33857
- Published
- May 4, 2026
- Updated
- May 4, 2026
- Vendor
- The Apache Software Foundation
- Product
- Apache HTTP Server
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 4, 2026CVE publishedPublication date reported by the CVE source.
- May 4, 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 <=2.4.66
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What is affected?
Published CVSS scores
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Attacks
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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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