Medium [CVE-2026-12549 +1] Libsoup: incomplete fix for CVE-2026-2443: range suffix overflow in libsoup soupserver
This medium-severity Red Hat Linux advisory covers CVE-2026-12549 and CVE-2026-2443 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations. This bulletin covers 2 CVEs; its score, affected versions and guidance may apply to different issues within that bulletin.
VulniPulse record published
Summary
The fix for CVE-2026-2443 was regressed by a subsequent rework commit that replaced specific overflow checks with a general signed comparison. When a client sends a Range request with a suffix length exceeding the content size, the resulting negative start value is not properly clamped, leading to malformed HTTP 206 responses and log flooding.
This vulnerability is rated Moderate for Red Hat because it requires a non-default configuration where max_incoming_payload_size is explicitly set to 0 or unset in libsoup's WebSocket frame processing. In typical Red Hat deployments, this configuration is not enabled by default, limiting the exposure to memory disclosure or application instability.
Red Hat severity: Moderate — CVSS 4.8 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L). Weakness: CWE-805.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: libsoup3.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 4 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 4 days ago·verify at source
Mitigation checklist
- To mitigate this issue, applications utilizing libsoup's WebSocket support should ensure that the `max_incoming_payload_size` is explicitly set to a non-zero value. This prevents the library from processing WebSocket frames with an unset or zero maximum payload size, which can lead to out-of-bounds reads. Consult application-specific documentation for configuring libsoup parameters.
Official advisory · high-confidence parse· fetched 4 days ago·verify at source
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