CVE-2026-77680

*** Pendiente de traducción *** An algorithmic complexity flaw exists in libsoup&amp;#39;s HTTP Range header processing that persists after the CVE-2025-32907 fix.<br /> <br /> 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.<br /> <br /> 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&amp;#39;s event loop for that duration.<br /> <br /> This is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs.<br /> <br /> Affected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550.<br /> 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.<br /> Upstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538<br /> Related: CVE-2025-32907