CVE-2026-29035
Description
A flaw was found in CivetWeb. An unauthenticated remote attacker could exploit a heap and stack buffer overflow vulnerability by sending specially crafted compressed WebSocket frames. This could lead to memory corruption, potentially resulting in denial of service or arbitrary code execution. The vulnerability occurs during the permessage-deflate decompression process when specific experimental interfaces are enabled.
Statement
This vulnerability is rated Important because unauthenticated remote attackers can exploit a heap and stack buffer overflow in CivetWeb, potentially leading to denial of service or arbitrary code execution. Exploitation requires the USE_ZLIB and MG_EXPERIMENTAL_INTERFACES features to be enabled, which are not default configurations in Red Hat products.
Mitigation
To mitigate this vulnerability, ensure that CivetWeb is compiled without the `USE_ZLIB` and `MG_EXPERIMENTAL_INTERFACES` flags enabled. If CivetWeb is deployed as a library, applications linking against it should avoid enabling these experimental WebSocket features. Disabling these features prevents the vulnerable code path from being active.
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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