CVE-2026-64613
Data::Buffer::Shared versions before 0.05 for Perl create a world-readable mmap backing file and open it without O_NOFOLLOW
The segment is created in buf_generic.h with open(path, O_RDWR|O_CREAT|O_EXCL, 0666). O_EXCL blocks a pre-seeded file on create, but the mode is 0666, so under the default umask 022 the file is created mode 0644 (world-readable), and O_NOFOLLOW is absent, so a symlink planted at the path is followed when the segment is attached.
A "Shared" segment naturally lives in a shared directory such as /tmp or /dev/shm, where any local user can read the IPC payloads stored in the world-readable segment, and a pre-planted symlink at the path redirects the open to another file.
Affected Products
-
CVE record
-
NVD configurations
No data
-
Red Hat packages
No data
-
OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| EGOR | Data::Buffer::Shared | unaffected |
|
No data.
No data.
| Vendor | Product | Versions | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Egor | Data::buffer::shared |
|
Remediation
Vendor Solution
Upgrade to Data::Buffer::Shared 0.05 or later, which creates the backing file mode 0600 (owner-only) with O_NOFOLLOW.
Vendor Workaround
For deployments that cannot upgrade to 0.05, set a restrictive umask so the backing file is not world-readable and place it in a directory only the owning user can access.
Tracking
Advisories
Metrics
No CVSS v4.0
Attack Vector Local
Attack Complexity Low
Privileges Required None
Scope Unchanged
Confidentiality Impact High
Integrity Impact None
Availability Impact None
User Interaction None
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.176% probability within 30 days)
Exploitation none
Automatable no
Technical Impact partial
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Egor
Egor data::buffer::shared |
|
| Vendors & Products |
Egor
Egor data::buffer::shared |
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
|
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Data::Buffer::Shared versions before 0.05 for Perl create a world-readable mmap backing file and open it without O_NOFOLLOW. The segment is created in buf_generic.h with open(path, O_RDWR|O_CREAT|O_EXCL, 0666). O_EXCL blocks a pre-seeded file on create, but the mode is 0666, so under the default umask 022 the file is created mode 0644 (world-readable), and O_NOFOLLOW is absent, so a symlink planted at the path is followed when the segment is attached. A "Shared" segment naturally lives in a shared directory such as /tmp or /dev/shm, where any local user can read the IPC payloads stored in the world-readable segment, and a pre-planted symlink at the path redirects the open to another file. | |
| Title | Data::Buffer::Shared versions before 0.05 for Perl create a world-readable mmap backing file and open it without O_NOFOLLOW | |
| Weaknesses | CWE-59 CWE-732 |
|
| References |
|
