CVE-2026-77680

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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(N\u00b2) work coalescing them into a single range.\n\nThe 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.\n\nThis is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs.\n\nAffected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550.\nFixed 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.\nUpstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538\nRelated: CVE-2025-32907"}], "affected": [{"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "libsoup3", "defaultStatus": "affected", "cpes": ["cpe:/a:redhat:enterprise_linux:10"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2025-32907", "name": "CVE-2025-32907", "tags": ["technical-description", "x_refsource_REDHAT"]}, {"url": "https://access.redhat.com/security/cve/CVE-2026-77680", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520892", "name": "RHBZ#2520892", "tags": ["issue-tracking", "x_refsource_REDHAT"]}, {"url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/538"}, {"url": "https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550"}], "datePublic": "2026-08-21T00:00:00.000Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-407", "description": "Inefficient Algorithmic Complexity", "lang": "en", "type": "CWE"}]}], "x_redhatCweChain": "CWE-407: Inefficient Algorithmic Complexity", "workarounds": [{"lang": "en", "value": "Upgrade to a libsoup version containing merge request !550 (O(N) range coalescing and 200-range limit). Until patched, restrict network access to services using SoupServer, or terminate connections that send Range headers with excessive range counts."}], "timeline": [{"lang": "en", "time": "2026-08-21T00:00:00.000Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-08-21T00:00:00.000Z", "value": "Made public."}], "credits": [{"lang": "en", "value": "Red Hat would like to thank Jianqiang (Stark) Li for reporting this issue."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-11-06T00:45:32.456Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"references": [{"url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/538", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-08-26T12:38:58.296657Z", "id": "CVE-2026-77680", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-08-26T12:43:47.896Z"}}]}}

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Until patched, restrict network access to services using SoupServer, or terminate connections that send Range headers with excessive range counts."}], "x_generator": {"engine": "cvelib 1.8.0"}, "descriptions": [{"lang": "en", "value": "An algorithmic complexity flaw exists in libsoup's HTTP Range header processing that persists after the CVE-2025-32907 fix.\n\nCVE-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(N\u00b2) work coalescing them into a single range.\n\nThe 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.\n\nThis is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs.\n\nAffected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550.\nFixed 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.\nUpstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538\nRelated: CVE-2025-32907"}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-407", "description": "Inefficient Algorithmic Complexity"}]}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-11-06T00:45:32.456Z"}, "x_redhatCweChain": "CWE-407: Inefficient Algorithmic Complexity"}}, "cveMetadata": {"cveId": "CVE-2026-77680", "state": "PUBLISHED", "dateUpdated": "2026-11-06T00:45:32.456Z", "dateReserved": "2026-08-21T05:11:09.007Z", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "datePublished": "2026-08-25T20:36:45.808Z", "assignerShortName": "redhat"}, "dataVersion": "5.2"}

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{"acknowledgement": "Red Hat would like to thank Jianqiang (Stark) Li for reporting this issue.", "bugzilla": {"description": "libsoup3: libsoup: quadratic CPU denial of service in HTTP Range coalescing after CVE-2025-32907 fix", "id": "2520892", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520892"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "status": "draft"}, "cwe": "CWE-407", "details": ["An algorithmic complexity flaw exists in libsoup's HTTP Range header processing that persists after the CVE-2025-32907 fix.\nCVE-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(N\u00b2) work coalescing them into a single range.\nThe 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.\nThis is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs.\nAffected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550.\nFixed 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.\nUpstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538\nRelated: CVE-2025-32907"], "mitigation": {"lang": "en:us", "value": "Upgrade to a libsoup version containing merge request !550 (O(N) range coalescing and 200-range limit). Until patched, restrict network access to services using SoupServer, or terminate connections that send Range headers with excessive range counts."}, "name": "CVE-2026-77680", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "libsoup3", "product_name": "Red Hat Enterprise Linux 10"}], "public_date": "2026-08-21T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-77680\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-77680\nhttps://gitlab.gnome.org/GNOME/libsoup/-/issues/538\nhttps://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550"], "statement": "An inefficient algorithm flaw was found in libsoup. After the fix for CVE-2025-32907, coalescing overlapping HTTP Range values still performed quadratic work when many identical ranges were supplied in one request. A remote attacker could send a crafted HTTP request to a SoupServer-based application to consume excessive CPU and reduce availability for other clients.", "threat_severity": "Moderate"}

{"created": "2026-08-26T01:45:03.414219+00:00", "updated": "2026-08-26T01:45:03.414224+00:00", "vendors": []}