CVE-2026-15396

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory published 2026-09-14. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 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.

IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By sending a specially crafted HTTP transfer-encoding request header, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.

CVSS v3
6.5
EG Score
6.5(high)
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
17%
KEV
Not listed

Published

September 14, 2026

Last Modified

September 16, 2026

Advisory Details (1)

Auto-updated Sep 14, 2026
No patch confirmed yet.
generic

Security Bulletin: IBM WebSphere Application Server prior to 9.0.5.29 and 8.5.5.31 are affected by multiple vulnerabilities

https://www.ibm.com/support/pages/node/7286610

Vendor Advisories for CVE-2026-15396(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 19× in last 7d / 19× 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. 2026-09-19 15:16 UTCEG score recompute
  2. 2026-09-19 15:16 UTCGHSA enrichment
  3. 2026-09-18 19:27 UTCEPSS rescore
  4. 2026-09-18 17:21 UTCEG score recompute
  5. 2026-09-18 17:21 UTCGHSA enrichment
  6. 2026-09-17 19:25 UTCGHSA enrichment
  7. 2026-09-16 19:35 UTCEG score recompute
  8. 2026-09-16 19:35 UTCGHSA enrichment
  9. 2026-09-16 14:07 UTCEPSS rescore
  10. 2026-09-16 13:49 UTCEG score recompute
  11. 2026-09-16 13:49 UTCGHSA enrichment
  12. 2026-09-16 05:14 UTCEPSS rescore
  13. 2026-09-15 15:32 UTCEG score recompute
  14. 2026-09-15 15:32 UTCGHSA enrichment
  15. 2026-09-15 14:43 UTCEG score recompute
  16. 2026-09-15 14:43 UTCGHSA enrichment
  17. 2026-09-14 20:21 UTCEG score recompute
  18. 2026-09-14 20:15 UTCEG score recompute
  19. 2026-09-14 20:14 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-15396?
CVE-2026-15396 is a medium vulnerability published on September 14, 2026. IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By sending a specially crafted HTTP transfer-encoding request header, an attacker could…
When was CVE-2026-15396 disclosed?
CVE-2026-15396 was first published in the National Vulnerability Database on September 14, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-15396 actively exploited?
CVE-2026-15396 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 83.0% of all scored CVEs.
What is the CVSS score of CVE-2026-15396?
CVE-2026-15396 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-15396?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15396, 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

Explore the affected products and dependency analysis for CVE-2026-15396

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