Libsoup2.4: A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs… (CVE-2026-66338)
A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.
Libsoup2.4: A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs… (CVE-2026-66338)
Description
A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.
CVSS v3.1
Score 7.2high
Weaknesses
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-8wm8-3499-x4v9
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-66338"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a6542159c2644c7f8087677
Added to database: 07/25/2026, 23:09:09 UTC
Last enriched: 07/25/2026, 23:47:42 UTC
Last updated: 09/07/2026, 22:52:14 UTC
Views: 121
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