Off-by-one out-of-bounds read in Apache HTTP Server mod_proxy_ajp AJP getter functions
CVE-2026-33857 is an out-of-bounds read vulnerability in Apache HTTP Server's mod_proxy_ajp module. The flaw is described as an off-by-one out-of-bounds read in AJP getter functions used while processing AJP protocol data. It affects Apache HTTP Server versions through 2.4.66 and was fixed in 2.4.67. Based on the available information, the issue allows a remote attacker to trigger a read past the intended buffer boundary during AJP-related request handling, resulting primarily in unintended memory disclosure rather than modification or code execution.
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Impact
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Mitigation
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Exploits
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No public exploit code observed for this vulnerability.
Affected products & vendors
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Recent activity
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An out-of-bounds read vulnerability in Apache HTTP Server's AJP getter functions caused by an off-by-one error. It is remotely exploitable over the network and may allow limited information disclosure.
Apache HTTP Server mod_proxy_ajp vulnerability leading to a server crash or denial-of-service condition.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.