CVE-2026-4271

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.8%, top 46% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: Elevated riskExposed: 0

A fix is available — apply it.

A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the application attempting to access memory that has already been freed, potentially causing application instability or crashes, resulting in a Denial of Service (DoS).

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: 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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
55%
KEV
Not listed

Published

March 17, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated May 12, 2026
🔬 Proof of concept available. Patch available. Sources: redhat.
generic🟡 PoC Available

(CVE-2026-4271) (#YWH-PGM9867-167) Use After Free on libsoup through libsoup/server/http2/soup-server-message-io-http2.c via "on_frame_recv_callback()" (#496) · Issues · GNOME / libsoup · GitLab

https://gitlab.gnome.org/GNOME/libsoup/-/issues/496
redhat Patch Available

2448044 – (CVE-2026-4271) CVE-2026-4271 libsoup: libsoup: Denial of Service via Use-After-Free in HTTP/2 server

Affected: Red Hat Enterprise Linux 10

https://bugzilla.redhat.com/show_bug.cgi?id=2448044
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-4271
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:15968

Vendor Advisories for CVE-2026-4271(4)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatlibsoup3-0:3.6.5-3.el10_2.112026-05-19redhat
redhatlibsoup3-0:3.6.5-3.el10_0.152026-05-14redhat
redhatlibsoup3-0:3.6.5-3.el10_1.112026-05-11redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

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 6× in last 7d / 58× 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 175 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 14:12 UTCEPSS rescore
  3. 2026-09-01 13:54 UTCEPSS rescore
  4. 2026-09-01 04:40 UTCEPSS rescore
  5. 2026-08-30 19:17 UTCEPSS rescore
  6. 2026-08-30 01:22 UTCEPSS rescore
  7. 2026-08-28 21:41 UTCEPSS rescore
  8. 2026-08-27 14:25 UTCEPSS rescore
  9. 2026-08-26 14:46 UTCEPSS rescore
  10. 2026-08-25 13:49 UTCEPSS rescore
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-20 22:55 UTCEPSS rescore
  14. 2026-08-19 17:04 UTCEPSS rescore
  15. 2026-08-18 13:48 UTCEPSS rescore
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 14:56 UTCEPSS rescore
  18. 2026-08-16 11:22 UTCEG score recompute
  19. 2026-08-16 11:22 UTCVendor advisory
  20. 2026-08-16 11:22 UTCGHSA enrichment
  21. 2026-08-16 02:14 UTCEPSS rescore
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 20:05 UTCVendor advisory
  24. 2026-08-14 20:05 UTCGHSA enrichment
  25. 2026-08-14 07:29 UTCEG score recompute
Show 75 more
  1. 2026-08-14 07:29 UTCVendor advisory
  2. 2026-08-14 07:29 UTCGHSA enrichment
  3. 2026-08-13 22:00 UTCEPSS rescore
  4. 2026-08-12 22:16 UTCEG score recompute
  5. 2026-08-12 22:16 UTCVendor advisory
  6. 2026-08-12 22:16 UTCGHSA enrichment
  7. 2026-08-12 13:51 UTCEPSS rescore
  8. 2026-08-11 21:34 UTCEG score recompute
  9. 2026-08-11 21:34 UTCVendor advisory
  10. 2026-08-11 21:34 UTCGHSA enrichment
  11. 2026-08-11 04:41 UTCEG score recompute
  12. 2026-08-11 04:41 UTCVendor advisory
  13. 2026-08-11 04:41 UTCGHSA enrichment
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 08:18 UTCVendor advisory
  16. 2026-08-10 08:18 UTCGHSA enrichment
  17. 2026-08-09 19:40 UTCEG score recompute
  18. 2026-08-09 19:40 UTCVendor advisory
  19. 2026-08-09 19:40 UTCGHSA enrichment
  20. 2026-08-09 13:46 UTCEPSS rescore
  21. 2026-08-09 07:04 UTCEG score recompute
  22. 2026-08-09 07:04 UTCVendor advisory
  23. 2026-08-09 07:04 UTCGHSA enrichment
  24. 2026-08-08 16:37 UTCEPSS rescore
  25. 2026-08-08 06:18 UTCVendor advisory
  26. 2026-08-08 06:18 UTCGHSA enrichment
  27. 2026-08-07 17:42 UTCEG score recompute
  28. 2026-08-07 17:42 UTCVendor advisory
  29. 2026-08-07 17:42 UTCGHSA enrichment
  30. 2026-08-06 19:33 UTCEG score recompute
  31. 2026-08-06 19:33 UTCVendor advisory
  32. 2026-08-06 19:33 UTCGHSA enrichment
  33. 2026-08-06 13:47 UTCEPSS rescore
  34. 2026-08-06 01:43 UTCEG score recompute
  35. 2026-08-06 01:43 UTCVendor advisory
  36. 2026-08-06 01:43 UTCGHSA enrichment
  37. 2026-08-05 19:17 UTCEPSS rescore
  38. 2026-08-04 15:10 UTCEPSS rescore
  39. 2026-08-04 10:39 UTCEPSS rescore
  40. 2026-08-04 00:52 UTCEG score recompute
  41. 2026-08-04 00:52 UTCVendor advisory
  42. 2026-08-04 00:52 UTCGHSA enrichment
  43. 2026-08-03 10:36 UTCEPSS rescore
  44. 2026-08-02 16:50 UTCEG score recompute▲ 2.20
  45. 2026-08-02 16:50 UTCVendor advisory
  46. 2026-08-02 16:50 UTCGHSA enrichment
  47. 2026-08-02 02:27 UTCEPSS rescore
  48. 2026-08-01 04:16 UTCEPSS rescore
  49. 2026-07-30 16:28 UTCEPSS rescore
  50. 2026-07-30 01:30 UTCEPSS rescore
  51. 2026-07-28 15:37 UTCEPSS rescore
  52. 2026-07-26 14:54 UTCEPSS rescore
  53. 2026-07-25 14:18 UTCEPSS rescore
  54. 2026-07-24 14:18 UTCEPSS rescore
  55. 2026-07-23 14:18 UTCEPSS rescore
  56. 2026-07-23 03:11 UTCEG score recompute
  57. 2026-07-22 14:08 UTCEPSS rescore
  58. 2026-07-21 15:25 UTCEPSS rescore
  59. 2026-07-20 17:08 UTCEPSS rescore
  60. 2026-07-19 14:31 UTCEPSS rescore
  61. 2026-07-19 14:31 UTCEPSS rescore
  62. 2026-07-19 02:29 UTCEPSS rescore
  63. 2026-07-18 10:04 UTCEPSS rescore
  64. 2026-07-16 17:03 UTCEPSS rescore
  65. 2026-07-15 16:57 UTCEPSS rescore
  66. 2026-07-15 16:57 UTCEPSS rescore
  67. 2026-07-15 02:00 UTCEPSS rescore
  68. 2026-07-15 02:00 UTCEPSS rescore
  69. 2026-07-13 22:30 UTCEPSS rescore
  70. 2026-07-12 05:46 UTCEPSS rescore
  71. 2026-07-11 08:27 UTCEPSS rescore
  72. 2026-07-09 19:10 UTCEPSS rescore
  73. 2026-07-08 15:16 UTCEPSS rescore
  74. 2026-07-07 13:46 UTCEPSS rescore
  75. 2026-07-06 16:27 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-4271?
CVE-2026-4271 is a high vulnerability published on March 17, 2026. A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the…
When was CVE-2026-4271 disclosed?
CVE-2026-4271 was first published in the National Vulnerability Database on March 17, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4271 actively exploited?
CVE-2026-4271 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 44.9% of all scored CVEs.
What is the CVSS score of CVE-2026-4271?
CVE-2026-4271 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-4271?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4271, 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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