VulnerabilityAnalyzed
CVE-2026-66338
A flaw was found in libsoup.
HIGH 7.2EPSS 0.19%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 7.2 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- EPSS
- 0.19% probability · 9th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-444
- Affected
- gnome/libsoup · redhat/enterprise linux
- Source
- secalert@redhat.com
References
- https://access.redhat.com/security/cve/CVE-2026-66338Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2506950Exploit, Issue Tracking, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.