CVE-2026-59139 EGOR CVE debrief

Who should care

Users of Data::ReqRep::Shared versions before 0.05 for Perl should be concerned about this vulnerability. A local attacker with the ability to write to the backing file can exploit this vulnerability to read sensitive information or crash the process. Operators, platform administrators, vulnerability management teams, and security teams should review the official advisory and plan for updates or mitigations.

Technical summary

The vulnerability exists in the reqrep_recv_locked function of Data::ReqRep::Shared versions before 0.05 for Perl. The function performs a memcpy operation with arena_off and len read raw from the mmap'd segment, without bounding against the arena capacity. This allows a local peer to read adjacent memory or crash the process by poisoning a request slot's offset and length. The attach-time validator reqrep_validate_header checks the header scalars and region layout against the file size but does not validate the array contents.

Defensive priority

High

Recommended defensive actions

• Update Data::ReqRep::Shared to version 0.05 or later
• Restrict access to the backing file to prevent local attackers from writing to it
• Implement additional monitoring and logging to detect potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-07-21T19:17:11.467Z and was last modified on 2026-07-22T20:17:02.053Z. The NVD entry is currently Deferred. This vulnerability affects Data::ReqRep::Shared versions before 0.05 for Perl, allowing a local peer to read adjacent memory or crash the process by poisoning a request slot's offset and length. Evidence is based on the official CVE record and NVD entry. Defenders should verify affected product deployments, review official advisories, and plan vendor-supported updates or mitigations.

Official resources