CVE-2026-66337

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-07-25. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

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

A flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_read_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client application to crash or disclose sensitive heap memory.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

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
Severity65% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
13%
KEV
Not listed

Published

July 24, 2026

Last Modified

August 24, 2026

Advisory Details (2)

Auto-updated Jul 25, 2026
Patch available. Sources: redhat.
redhat

2506949 – (CVE-2026-66337) CVE-2026-66337 libsoup: libsoup: Heap buffer over-read via integer underflow in soup_filter_input_stream_read_until()

https://bugzilla.redhat.com/show_bug.cgi?id=2506949
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-66337

Vendor Advisories for CVE-2026-66337(1)

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

Affected Packages

(6 across 4 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:11(1)
PackageVulnerable rangeFixed inDependents
libsoup2.42.72.0-2 ... 2.74.3-9 (28 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 16× in last 7d / 83× 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.

Showing the most recent 100 of 107 total refreshes for this CVE.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-30 00:14 UTCEG score recompute
  3. 2026-08-30 00:14 UTCGHSA enrichment
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-27 11:49 UTCEG score recompute
  6. 2026-08-27 11:49 UTCGHSA enrichment
  7. 2026-08-26 14:47 UTCEPSS rescore
  8. 2026-08-26 13:39 UTCGHSA enrichment
  9. 2026-08-25 15:18 UTCEG score recompute
  10. 2026-08-25 15:18 UTCGHSA enrichment
  11. 2026-08-25 13:49 UTCEPSS rescore
  12. 2026-08-24 17:00 UTCGHSA enrichment
  13. 2026-08-24 15:14 UTCEG score recompute
  14. 2026-08-24 15:14 UTCGHSA enrichment
  15. 2026-08-23 17:03 UTCEG score recompute
  16. 2026-08-23 17:03 UTCGHSA enrichment
  17. 2026-08-23 00:19 UTCEPSS rescore
  18. 2026-08-22 18:53 UTCEG score recompute
  19. 2026-08-22 18:53 UTCGHSA enrichment
  20. 2026-08-21 23:49 UTCEPSS rescore
  21. 2026-08-21 20:43 UTCEG score recompute
  22. 2026-08-21 20:43 UTCGHSA enrichment
  23. 2026-08-20 22:56 UTCEPSS rescore
  24. 2026-08-20 22:33 UTCGHSA enrichment
  25. 2026-08-20 00:23 UTCEG score recompute
Show 75 more
  1. 2026-08-20 00:23 UTCGHSA enrichment
  2. 2026-08-19 17:04 UTCEPSS rescore
  3. 2026-08-19 02:13 UTCEG score recompute
  4. 2026-08-19 02:13 UTCGHSA enrichment
  5. 2026-08-18 13:48 UTCEPSS rescore
  6. 2026-08-18 04:04 UTCEG score recompute
  7. 2026-08-18 04:03 UTCGHSA enrichment
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-17 05:48 UTCEG score recompute
  10. 2026-08-17 05:48 UTCGHSA enrichment
  11. 2026-08-16 14:56 UTCEPSS rescore
  12. 2026-08-16 06:59 UTCEG score recompute
  13. 2026-08-16 06:59 UTCGHSA enrichment
  14. 2026-08-15 08:50 UTCEG score recompute
  15. 2026-08-15 08:50 UTCGHSA enrichment
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-14 10:40 UTCEG score recompute
  18. 2026-08-14 10:40 UTCGHSA enrichment
  19. 2026-08-13 22:00 UTCEPSS rescore
  20. 2026-08-13 12:30 UTCGHSA enrichment
  21. 2026-08-12 14:20 UTCEG score recompute
  22. 2026-08-12 14:20 UTCGHSA enrichment
  23. 2026-08-12 13:51 UTCEPSS rescore
  24. 2026-08-11 16:10 UTCEG score recompute
  25. 2026-08-11 16:10 UTCGHSA enrichment
  26. 2026-08-11 00:00 UTCEPSS rescore
  27. 2026-08-10 18:01 UTCGHSA enrichment
  28. 2026-08-09 19:39 UTCEG score recompute
  29. 2026-08-09 19:39 UTCGHSA enrichment
  30. 2026-08-09 13:47 UTCEPSS rescore
  31. 2026-08-08 21:30 UTCEG score recompute
  32. 2026-08-08 21:30 UTCGHSA enrichment
  33. 2026-08-08 16:37 UTCEPSS rescore
  34. 2026-08-07 23:20 UTCEG score recompute
  35. 2026-08-07 23:20 UTCGHSA enrichment
  36. 2026-08-07 01:10 UTCEG score recompute
  37. 2026-08-07 01:10 UTCGHSA enrichment
  38. 2026-08-06 13:47 UTCEPSS rescore
  39. 2026-08-06 03:00 UTCEG score recompute
  40. 2026-08-06 03:00 UTCGHSA enrichment
  41. 2026-08-05 19:17 UTCEPSS rescore
  42. 2026-08-05 19:17 UTCEPSS rescore
  43. 2026-08-05 04:51 UTCEG score recompute
  44. 2026-08-05 04:51 UTCGHSA enrichment
  45. 2026-08-04 15:10 UTCEPSS rescore
  46. 2026-08-04 10:39 UTCEPSS rescore
  47. 2026-08-04 06:42 UTCEG score recompute
  48. 2026-08-04 06:41 UTCGHSA enrichment
  49. 2026-08-03 10:36 UTCEPSS rescore
  50. 2026-08-03 08:27 UTCGHSA enrichment
  51. 2026-08-02 10:15 UTCEG score recompute
  52. 2026-08-02 10:15 UTCGHSA enrichment
  53. 2026-08-02 02:27 UTCEPSS rescore
  54. 2026-08-01 12:06 UTCEG score recompute
  55. 2026-08-01 12:06 UTCGHSA enrichment
  56. 2026-08-01 04:16 UTCEPSS rescore
  57. 2026-07-31 13:56 UTCEG score recompute
  58. 2026-07-31 13:56 UTCGHSA enrichment
  59. 2026-07-30 16:28 UTCEPSS rescore
  60. 2026-07-30 15:46 UTCEG score recompute
  61. 2026-07-30 15:45 UTCGHSA enrichment
  62. 2026-07-30 01:30 UTCEPSS rescore
  63. 2026-07-29 17:03 UTCGHSA enrichment
  64. 2026-07-28 18:53 UTCEG score recompute
  65. 2026-07-28 18:53 UTCGHSA enrichment
  66. 2026-07-28 15:37 UTCEPSS rescore
  67. 2026-07-27 20:43 UTCGHSA enrichment
  68. 2026-07-27 16:26 UTCEG score recompute
  69. 2026-07-27 16:26 UTCGHSA enrichment
  70. 2026-07-27 16:17 UTCEG score recompute
  71. 2026-07-27 16:17 UTCGHSA enrichment
  72. 2026-07-27 14:14 UTCEPSS rescore
  73. 2026-07-27 07:53 UTCEG score recompute
  74. 2026-07-27 07:52 UTCGHSA enrichment
  75. 2026-07-26 14:54 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66337?
CVE-2026-66337 is a medium vulnerability published on July 24, 2026. A flaw was found in libsoup. An unsigned integer underflow in the soupfilterinputstreamread_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client…
When was CVE-2026-66337 disclosed?
CVE-2026-66337 was first published in the National Vulnerability Database on July 24, 2026, with the most recent update on August 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66337 actively exploited?
CVE-2026-66337 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 86.8% of all scored CVEs.
What is the CVSS score of CVE-2026-66337?
CVE-2026-66337 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-66337?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66337, 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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