HTTP::Body for Perl drops mixed-case percent escapes from form fields
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
HTTP::Body for Perl versions before 1.23_01 drops mixed-case percent escapes from urlencoded form fields instead of decoding them. The decode table covers only all-lowercase and all-uppercase hex pairs, so an escape such as %aB is replaced with nothing (CWE-178). A remote attacker can send field names or values that a conforming decoder in front of the application reads differently, so the application receives altered field names.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Description from the CNA
HTTP::Body versions before 1.23_01 for Perl drop mixed-case percent escapes from urlencoded form fields instead of decoding them. The decode table holds only the all-lowercase and all-uppercase spelling of each hex pair, while the escape pattern matches either case. An escape such as %aB finds no entry and is replaced with nothing, joining the bytes on either side. Hex digits in percent escapes are case-insensitive, and conforming decoders return the byte. A remote attacker can send a field name or value that a conforming decoder in front of the application reads differently, so that pass%aBword reaches the application as password.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
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 |
|---|---|---|---|---|---|
| — | HTTP-Body | before 1.23_01 | 1.23_01 | Patch available | CNA |
- HTTP-Body Vendor— Affected before 1.23_01 Fixed in 1.23_01 Patch available CNA
Remediation
Upgrade HTTP-Body to version 1.23_01, the fixed version. The sources list no vendor advisory identifier for this fix.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
- Fix · CNA HTTP-Body Fixed in 1.23_01
Vendor assessments
Timeline
- 2026-10-28 Threatist record created from CVE-2026-116135
- 2026-10-28 Alias added: GHSA-xw3w-872r-g8q5
- 2026-10-30 Affected versions changed · Red Hat
- 2026-10-30 CVSS score added · Red Hat
- 2026-11-05 CVSS score added · CISA ADP
- 2026-11-05 CISA SSVC decision points changed
- 2026-11-05 Priority changed: LOW → MEDIUM
References
Sources
- CVE-2026-116135 · CVE Program
- CVE-2026-116135 · NVD
- FIRST EPSS
- GHSA-xw3w-872r-g8q5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-116135 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences