CVE-2026-59139 Memory corruption in Data::ReqRep::Shared
A local attacker can trigger an out-of-bounds read in the Perl Data::ReqRep::Shared library by manipulating a shared memory file, leading to information disclosure or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-59139?
CVE-2026-59139 is a critical memory corruption vulnerability in EGOR Data::ReqRep::Shared, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Data::ReqRep::Shared versions before 0.05 for Perl allow an out-of-bounds read via an unvalidated arena offset and length in reqrep_recv_locked.
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 it then trusts. reqrep_recv_locked does memcpy(copy_buf, req_arena + arena_off, len) with arena_off and len read raw from the mmap'd segment and never bounded against the arena capacity (req_arena_cap).
A local peer that can write the backing file can leave the header valid while poisoning a request slot's offset and length, so receiving the request copies a file-controlled offset and length out of the arena, reading adjacent memory or crashing the process.
Weakness: CWE-125
Which versions are affected by CVE-2026-59139?
How do I fix CVE-2026-59139?
No fix has been published for CVE-2026-59139 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-59139 being exploited?
There is no known exploitation of CVE-2026-59139 in the wild and no public exploit code.
Sources
Also known as GHSA-3jgv-34p5-3fxv.