CVE-2026-77680

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH confidence

Score 5.3 from GitHub Security Advisory published 2026-08-25. a secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
5.3
EG Score
5.3(high)
EG Risk
55(Attend)
EG Risk 55/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
28%
KEV
Not listed

Published

August 25, 2026

Last Modified

August 28, 2026

Advisory Details (5)

Auto-updated Aug 25, 2026
🔬 Proof of concept available. Patch available. Sources: redhat.
generic

message-headers: Fix Range and Content-Range parsing (!550) · Merge requests · GNOME / libsoup · GitLab

https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550
generic🟡 PoC Available

(CVE-2026-77680) Incomplete fix for CVE-2025-32907: Range-coalescing DoS persists as O(N²) CPU exhaustion on patched libsoup (#538) · Issues · GNOME / libsoup · GitLab

https://gitlab.gnome.org/GNOME/libsoup/-/issues/538
redhat

Bug Access Denied

https://bugzilla.redhat.com/show_bug.cgi?id=2520892
redhat Patch Available

CVE-2026-77680 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-77680
redhat Patch Available

CVE-2025-32907 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2025-32907

Vendor Advisories for CVE-2026-77680(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFixed inDependents
libsoup2.42.74.3-1 ... 2.74.3-9 (16 versions)——
libsoup33.2.2-2 ... 3.6.6-1 (35 versions)——
Debian:13(2)
PackageVulnerable rangeFixed inDependents
libsoup2.42.74.3-10.1, 2.74.3-11——
libsoup33.6.5-3 ... 3.6.6-1 (8 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libsoup33.6.5-3 ... 3.6.6-1 (8 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 19× in last 7d / 69× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 21:32 UTCEG score recompute
  2. 2026-09-18 21:32 UTCGHSA enrichment
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-17 21:01 UTCEG score recompute
  5. 2026-09-17 21:01 UTCGHSA enrichment
  6. 2026-09-16 19:14 UTCEG score recompute
  7. 2026-09-16 19:14 UTCGHSA enrichment
  8. 2026-09-16 14:08 UTCEPSS rescore
  9. 2026-09-16 05:15 UTCEPSS rescore
  10. 2026-09-15 19:45 UTCEG score recompute
  11. 2026-09-15 19:45 UTCGHSA enrichment
  12. 2026-09-15 03:12 UTCEPSS rescore
  13. 2026-09-15 03:12 UTCEPSS rescore
  14. 2026-09-14 20:32 UTCGHSA enrichment
  15. 2026-09-13 21:29 UTCEG score recompute
  16. 2026-09-13 21:29 UTCGHSA enrichment
  17. 2026-09-12 22:26 UTCEG score recompute
  18. 2026-09-12 22:26 UTCGHSA enrichment
  19. 2026-09-12 15:02 UTCEPSS rescore
  20. 2026-09-11 23:22 UTCEG score recompute
  21. 2026-09-11 23:22 UTCGHSA enrichment
  22. 2026-09-11 14:53 UTCEPSS rescore
  23. 2026-09-10 23:16 UTCEG score recompute
  24. 2026-09-10 23:16 UTCGHSA enrichment
  25. 2026-09-10 09:35 UTCEPSS rescore
Show 44 more
  1. 2026-09-10 00:12 UTCGHSA enrichment
  2. 2026-09-09 00:56 UTCEG score recompute
  3. 2026-09-09 00:56 UTCGHSA enrichment
  4. 2026-09-08 22:01 UTCEPSS rescore
  5. 2026-09-07 15:14 UTCEG score recompute
  6. 2026-09-07 15:14 UTCGHSA enrichment
  7. 2026-09-06 13:48 UTCEPSS rescore
  8. 2026-09-06 13:12 UTCEG score recompute
  9. 2026-09-06 13:12 UTCGHSA enrichment
  10. 2026-09-05 14:09 UTCGHSA enrichment
  11. 2026-09-04 15:03 UTCEG score recompute
  12. 2026-09-04 15:03 UTCGHSA enrichment
  13. 2026-09-04 05:07 UTCEPSS rescore
  14. 2026-09-03 15:58 UTCGHSA enrichment
  15. 2026-09-02 16:46 UTCEG score recompute
  16. 2026-09-02 16:46 UTCGHSA enrichment
  17. 2026-09-02 14:12 UTCEPSS rescore
  18. 2026-09-01 17:42 UTCEG score recompute
  19. 2026-09-01 17:42 UTCGHSA enrichment
  20. 2026-09-01 13:54 UTCEPSS rescore
  21. 2026-09-01 04:40 UTCEPSS rescore
  22. 2026-09-01 04:40 UTCEPSS rescore
  23. 2026-08-31 18:39 UTCGHSA enrichment
  24. 2026-08-30 19:29 UTCEG score recompute
  25. 2026-08-30 19:29 UTCGHSA enrichment
  26. 2026-08-30 19:18 UTCEPSS rescore
  27. 2026-08-30 19:17 UTCEPSS rescore
  28. 2026-08-30 01:22 UTCEPSS rescore
  29. 2026-08-29 20:27 UTCEG score recompute
  30. 2026-08-29 20:27 UTCGHSA enrichment
  31. 2026-08-28 21:42 UTCEPSS rescore
  32. 2026-08-28 21:24 UTCGHSA enrichment
  33. 2026-08-28 13:50 UTCGHSA enrichment
  34. 2026-08-27 14:46 UTCEG score recompute
  35. 2026-08-27 14:46 UTCGHSA enrichment
  36. 2026-08-27 14:25 UTCEPSS rescore
  37. 2026-08-26 15:43 UTCEG score recompute
  38. 2026-08-26 15:43 UTCGHSA enrichment
  39. 2026-08-26 14:47 UTCEPSS rescore
  40. 2026-08-26 12:58 UTCEG score recompute
  41. 2026-08-26 12:58 UTCGHSA enrichment
  42. 2026-08-25 21:26 UTCEG score recompute
  43. 2026-08-25 20:55 UTCEG score recompute
  44. 2026-08-25 20:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77680?
CVE-2026-77680 is a medium vulnerability published on August 25, 2026. 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…
When was CVE-2026-77680 disclosed?
CVE-2026-77680 was first published in the National Vulnerability Database on August 25, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77680 actively exploited?
CVE-2026-77680 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 72.0% of all scored CVEs.
What is the CVSS score of CVE-2026-77680?
CVE-2026-77680 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-77680?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77680, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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