Red Hat Enterprise Linux Range Coalescing soup-message-headers.c soup_message_headers_get_ranges_internal resource consumption

Summaryinfo

A vulnerability labeled as problematic has been found in Red Hat Enterprise Linux. Affected by this issue is the function soup_message_headers_get_ranges_internal of the file libsoup/soup-message-headers.c of the component Range Coalescing. The manipulation results in resource consumption. This vulnerability is identified as CVE-2026-77680. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Red Hat Enterprise Linux (the affected version unknown). It has been classified as problematic. Affected is the function soup_message_headers_get_ranges_internal of the file libsoup/soup-message-headers.c of the component Range Coalescing. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

An algorithmic complexity flaw exists in libsoup's HTTP Range header processing that persists after the CVE-2025-32907 fix. CVE-2025-32907 addressed memory amplification when a client repeated the same range many times in a single Range header. Commit 9bb92f7a corrected merge correctness in soup_message_headers_get_ranges_internal() in libsoup/soup-message-headers.c, but the coalescing loop still removes merged ranges using g_array_remove_index() for each coalesced element. Because GArray is contiguous, each mid-array removal performs an O(N) memmove. When many identical satisfiable ranges are supplied (for example bytes=0-0 repeated thousands of times), the loop performs O(N²) work coalescing them into a single range. The vulnerable path is reachable server-side from handle_partial_get() in libsoup/server/http1/soup-server-message-io-http1.c when a SoupServer handler returns HTTP 200 with a non-empty body. No authentication is required. The number of ranges is bounded only by the maximum request header size (~100 KiB), allowing roughly 25,000 ranges per request. Reporter measurements on libsoup HEAD containing the CVE-2025-32907 fix show ~90 ms single-core CPU per such request at the wire maximum, blocking the server's event loop for that duration. This is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs. Affected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550. Fixed upstream: MR !550 merged 2026-08-20, replacing per-element removal with O(N) in-place compaction and rejecting Range headers requesting more than 200 ranges. Upstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538 Related: CVE-2025-32907

The advisory is available at access.redhat.com. This vulnerability is traded as CVE-2026-77680 since 08/21/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/25/2026). This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Applying the patch MR !550 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Red Hat

Name

• Enterprise Linux

License

• commercial

Website

• Vendor: https://www.redhat.com/

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