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
56%
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 4× in last 7d / 20× 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 183 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Same vendor

1 shown

redhat:RHSA-2026:15968

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 44.0% 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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