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Vulnerability · Published Mar 17, 2026 · Assigned by redhat

CVE-2026-3633Libsoup: libsoup: header and http request injection via crlf injection

Low 3.9

In plain English

A low-severity security flaw in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).

Severity (CVSS 3.1)3.9Low
Exploit odds (30 days)0.2%top 85.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

A flaw was found in libsoup. A remote attacker, by controlling the method parameter of the `soup_message_new()` function, could inject arbitrary headers and additional request data. This vulnerability, known as CRLF (Carriage Return Line Feed) injection, occurs because the method value is not properly escaped during request line construction, potentially leading to HTTP request injection.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libsoup2.4no fix listedDEBIAN-CVE-2026-3633
Debian:13libsoup2.4no fix listedDEBIAN-CVE-2026-3633
Debian:12libsoup3no fix listedDEBIAN-CVE-2026-3633
Debian:13libsoup3no fix listedDEBIAN-CVE-2026-3633
Ubuntu:22.04:LTSlibsoup2.4no fix listedUBUNTU-CVE-2026-3633
Ubuntu:24.04:LTSlibsoup2.4no fix listedUBUNTU-CVE-2026-3633
Ubuntu:25.10libsoup2.4no fix listedUBUNTU-CVE-2026-3633
Ubuntu:26.10libsoup2.4no fix listedUBUNTU-CVE-2026-3633
Ubuntu:24.04:LTSlibsoup3no fix listedUBUNTU-CVE-2026-3633
Ubuntu:25.10libsoup3no fix listedUBUNTU-CVE-2026-3633
Ubuntu:26.04:LTSlibsoup3no fix listedUBUNTU-CVE-2026-3633
Ubuntu:26.10libsoup3no fix listedUBUNTU-CVE-2026-3633

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references

Weakness: CWE-93 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L

References