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TI-2026-25340 Aliases CVE-2026-32881GHSA-9w88-79f8-m3vp

ewe has an Overly Permissive List of Allowed Inputs

Priority MEDIUM 63CWE-183Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

ewe is a Gleam web server. ewe is a Gleam web server. Versions 0.6.0 through 3.0.4 are vulnerable to authentication bypass or spoofed proxy-trust headers. Chunked transfer encoding trailer handling merges declared trailer fields into req.headers after body parsing, but the denylist only blocks 9 header names. A malicious client can exploit this by declaring these headers in the Trailer field and appending them after the final chunk, causing request.set_header to overwrite legitimate values (e.g., those set by a reverse proxy). This enables attackers to forge authentication credentials, hijack sessions, bypass IP-based rate limiting, or spoof proxy-trust headers in any downstream middleware that reads headers after ewe.read_body is called. This issue has been fixed in version 3.0.5.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00402 34th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed ewe (vshakitskiy): 3.0.5ewe (Hex): 3.0.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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

VendorProductAffected versionsFixed inStatusSource
vshakitskiyewe0.6.0 to before 3.0.53.0.5Patch availableCNA
—ewe (Hex)0.6.0 to before 3.0.53.0.5Patch availableGHSA-9w88-79f8-m3vp
  • ewe Vendorvshakitskiy Affected 0.6.0 to before 3.0.5 Fixed in 3.0.5 Patch available CNA
  • ewe (Hex) Vendor— Affected 0.6.0 to before 3.0.5 Fixed in 3.0.5 Patch available GHSA-9w88-79f8-m3vp

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:vshakitskiy:ewe:*:*:*:*:*:*:*:*before 3.0.5Vulnerablevshakitskiy
  • cpe:2.3:a:vshakitskiy:ewe:*:*:*:*:*:*:*:* Versions before 3.0.5 Vulnerable ·vshakitskiy

Remediation

  • Fix · CNA ewe (vshakitskiy) Fixed in 3.0.5
  • Fix · GHSA-9w88-79f8-m3vp ewe (Hex) Fixed in 3.0.5 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-32881
  2. 2026-10-03 Alias added: GHSA-9w88-79f8-m3vp

References

Exploit 1

Patch 3

Advisory 1

Other 1

  • TI-2026-25333 ewe: Loop with Unreachable Exit Condition ('Infinite Loop') CVSS 3.1HIGH 7.5
  • TI-2026-26959 ewe Has Improper Neutralization of CRLF Sequences in HTTP Headers (HTTP Request/Response Splitting) CVSS 3.1MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences