Bug 2452951 (CVE-2026-3945)

Summary: CVE-2026-3945 tinyproxy: tinyproxy: Denial of Service via integer overflow in HTTP chunked transfer encoding parser
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in tinyproxy. An unauthenticated remote attacker can exploit an integer overflow vulnerability in the HTTP chunked transfer encoding parser. By sending a crafted HTTP request with a specially formed chunk size, the attacker can cause the proxy to miscalculate the size of incoming data. This leads to the proxy attempting to read an excessively large amount of data, holding worker connections open indefinitely and exhausting all available worker slots, resulting in a complete Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2452968, 2452969    
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Description OSIDB Bzimport 2026-03-30 08:01:51 UTC 
An integer overflow vulnerability in the HTTP chunked transfer encoding parser in tinyproxy up to and including version 1.11.3 allows an unauthenticated remote attacker to cause a denial of service (DoS). The issue occurs because chunk size values are parsed using strtol() without properly validating overflow conditions (e.g., errno == ERANGE). A crafted chunk size such as 0x7fffffffffffffff (LONG_MAX) bypasses the existing validation check (chunklen < 0), leading to a signed integer overflow during arithmetic operations (chunklen + 2). This results in incorrect size calculations, causing the proxy to attempt reading an extremely large amount of request-body data and holding worker connections open indefinitely. An attacker can exploit this behavior to exhaust all available worker slots, preventing new connections from being accepted and causing complete service unavailability. Upstream addressed this issue in commit bb7edc4; however, the latest stable release (1.11.3) remains affected at the time of publication.