Inode numbers exposed in default ETag header of Plack ETag middleware
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-497.
Summary
Plack::Middleware::ETag versions from 0.04 before 0.06 for Perl disclose file inode numbers in the default ETag header. When the response body is a filehandle and the file_etag option is not set, the ETag is built from the file's inode number, modification time and size. Clients receiving affected responses can use the disclosed inode numbers to aid backend fingerprinting and correlation of files served through different URLs.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
Plack::Middleware::ETag versions from 0.04 before 0.06 for Perl disclose file inode numbers in the default ETag header. When the response body is a filehandle and the file_etag option is not set, the ETag is built from the file's inode number, modification time and size. Clients receiving affected responses may use the disclosed inode numbers to aid backend fingerprinting and correlation of files served through different URLs.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | Plack-Middleware-ETag | 0.04 to before 0.06 | 0.06 | Patch available | CNA |
- Plack-Middleware-ETag Vendor— Affected 0.04 to before 0.06 Fixed in 0.06 Patch available CNA
Remediation
Upgrade Plack-Middleware-ETag to version 0.06.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
- Fix · CNA Plack-Middleware-ETag Fixed in 0.06
Timeline
- 2026-10-20 Threatist record created from CVE-2026-111946
- 2026-10-29 CVSS score added · CISA ADP
- 2026-10-29 CISA SSVC decision points changed
References
Sources
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