CVE-2026-28898

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cisa-adp, epss
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0

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

swift-nio-http2's HTTP/2-to-HTTP/1.1 codec did not validate pseudo-header values for control characters before placing them into the translated HTTP/1.1 message. swift-nio-http2 1.44.1 adds validation of all pseudo-header values (:path, :authority, :scheme, :method, and :status) at both the HPACK header validation layer and the HTTP/2-to-HTTP/1.1 translation layer. Requests or responses containing CR, LF, or NUL bytes in any pseudo-header value are now rejected with a connection error. This issue is fixed in swift-nio-http2 1.44.1.

CVSS v3
5.3
EG Score
5.3(medium)
EPSS
9.1%
KEV
Not listed

Published

June 12, 2026

Last Modified

June 30, 2026

Advisory Details (1)

Auto-updated Jun 25, 2026
Patch available. Sources: github.
github Patch Available

SwiftNIO HTTP/2: HTTP/2-to-HTTP/1 Request Smuggling via unvalidated :path pseudo-header in HTTP2ToHTTP1Codec · CVE-2026-28898 · GitHub Advisory Database · GitHub

https://github.com/advisories/GHSA-4px2-pw77-vc85

Vendor Advisories for CVE-2026-28898(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 16× in last 7d / 30× 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. 2026-07-07 01:16 UTCEG score recompute
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 19:03 UTCEG score recompute
  7. 2026-07-05 02:30 UTCEPSS rescore
  8. 2026-07-04 20:06 UTCEG score recompute
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-03 21:09 UTCEG score recompute
  11. 2026-07-02 22:12 UTCEG score recompute
  12. 2026-07-01 23:12 UTCEG score recompute
  13. 2026-07-01 15:06 UTCEPSS rescore
  14. 2026-07-01 00:14 UTCEG score recompute
  15. 2026-06-30 23:22 UTCEPSS rescore
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-30 01:11 UTCEG score recompute
  18. 2026-06-29 14:06 UTCEPSS rescore
  19. 2026-06-29 02:13 UTCEG score recompute▲ 5.30
  20. 2026-06-28 14:07 UTCEPSS rescore
  21. 2026-06-28 14:07 UTCEPSS rescore
  22. 2026-06-28 04:56 UTCEPSS rescore
  23. 2026-06-28 04:56 UTCEPSS rescore
  24. 2026-06-27 03:08 UTCEPSS rescore
  25. 2026-06-25 21:50 UTCNVD updateCVSS v3 → 5.3 · severity → MEDIUM
Show 5 more
  1. 2026-06-25 19:49 UTCNVD update
  2. 2026-06-15 22:05 UTCEG score recompute
  3. 2026-06-14 23:18 UTCEPSS rescore
  4. 2026-06-13 23:00 UTCEPSS rescore
  5. 2026-06-12 15:11 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-28898?
CVE-2026-28898 is a medium vulnerability published on June 12, 2026. swift-nio-http2's HTTP/2-to-HTTP/1.1 codec did not validate pseudo-header values for control characters before placing them into the translated HTTP/1.1 message. swift-nio-http2 1.44.1 adds validation of all pseudo-header values (:path, :authority, :scheme, :method, and :status) at both the HPACK…
When was CVE-2026-28898 disclosed?
CVE-2026-28898 was first published in the National Vulnerability Database on June 12, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-28898 actively exploited?
CVE-2026-28898 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-28898?
CVE-2026-28898 has a CVSS v3.1 base score of 5.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-28898?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28898, 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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