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Out-of-bounds ReadWeakness · CWE-125

CVE-2026-59139

CRITICAL · 9.1 CVSS v3.1 Published 2026-07-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 4 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Data::ReqRep::Shared versions before 0.05 have an out-of-bounds read vulnerability in reqrep_recv_locked where memcpy uses unvalidated arena_offset and len values read directly from an mmap'd file. The header validator checks file size but not array contents, allowing a local attacker who can modify the backing file to poison offset/length fields and read arbitrary memory adjacent to the arena or crash the process.

MitigationUpgrade to Data::ReqRep::Shared version 0.05 or later, which adds bounds validation for arena offset and length against arena capacity before performing the memcpy operation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if Data::ReqRep::Shared Perl module is installed
    Run 'perl -MData::ReqRep::Shared -e 'print Data::ReqRep::Shared->VERSION' or list installed Perl modules via 'perldoc -t Data::ReqRep::Shared'
    Affected if The module is not installed or returns no version - not affected
  2. Verify the installed version
    Compare the returned version number to the affected range (versions before 0.05). If version 0.05 or later is shown, the vulnerability is patched.
    Affected if Installed version is lower than 0.05 (e.g., 0.04, 0.03, etc.) - likely affected
  3. Identify processes using shared memory segments
    Run 'ipcs -m' to list shared memory segments, then check which processes attach to them via 'ls -la /dev/shm/' and review application logs or config for Data::ReqRep::Shared usage
    Affected if The application uses Data::ReqRep::Shared and creates shared memory segments - potentially affected if version < 0.05
  4. Check file permissions on shared memory files
    Inspect permissions on shared memory segments or files used by the module (typically under /dev/shm or application-specific paths). Run 'ls -la <shm_path>' and review who has write access.
    Affected if Untrusted local users have write access to shared memory segments used by the module - conditions for exploitation exist

Affected if Data::ReqRep::Shared version is below 0.05 AND the module is actively used with shared memory segments that have insufficiently restricted write permissions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Data::ReqRep::Shared version 0.05 or later, which adds bounds validation for arena offset and length against arena capacity before performing the memcpy operation.

Recommended fix Moderate confidence

Data::ReqRep::Shared version 0.05 or later

  1. 1. Check the current installed version of Data::ReqRep::Shared by running: cpan -D Data::ReqRep::Shared or cpanm --info Data::ReqRep::Shared
  2. 2. If the installed version is before 0.05, upgrade the module using: cpan Data::ReqRep::Shared (system-wide) or cpanm Data::ReqRep::Shared (Perlbrew/local)
  3. 3. Verify the upgrade was successful by checking the new version with: cpan -D Data::ReqRep::Shared
  4. 4. If using the module in any Perl applications, restart those applications to ensure they load the updated module

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-59139 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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