CVE-2026-12087: Socket versions before 2.041 for Perl have an out-of-bounds heap read

Synopsis

An out-of-bounds heap read vulnerability exists in the Perl Socket module before version 2.041. The flaw is reachable over the network without any authentication, and occurs in the pack_ip_mreq_source() function where a length check is applied to the wrong argument, allowing adjacent heap memory to be read and returned to the caller. Successful exploitation leaks heap contents to the attacker and can cause a service crash. A patched-image rebuild at version 2.041 is available on HarborGuard for environments running an affected version of the Socket module.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The vulnerable function is exposed over the network, meaning an attacker must be able to reach the service across the internet or an internal network to supply a crafted argument.

• AuthenticationNot required

  No credentials or account are needed; an unauthenticated caller can invoke the vulnerable code path directly.

• Victim interactionNot required

  No user action or social engineering is required to trigger the out-of-bounds read.

• Attack complexityDetail

  The exploit is reliable and requires no special conditions, race timing, or knowledge of memory layout to produce a heap read.

Blast Radius

• The attacker receives raw heap memory contents from the process, which may include cryptographic material, session tokens, or other in-memory data adjacent to the buffer.
• Confidential data processed by the Perl application, such as connection credentials or internal state, can be exposed through the returned packed structure.
• Reading past the end of a heap buffer can corrupt allocator metadata or adjacent allocations, crashing the affected service and causing a denial of service.