CVE-2026-73495

HIGHPre-NVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 79% 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: epss, secondary
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.4Exploit: None knownExposed: 0

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

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and 1.0.0-M42, blaze-server can merge HTTP/1.1 chunked-body trailer fields into Request.headers. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject arbitrary header names and values, including X-Forwarded-For and internal authorization headers, that a fronting proxy sanitized from the request-header section, bypassing header-based trust decisions in the application. Any http4s application using BlazeServerBuilder over HTTP/1.1 whose routes or middleware trust proxy-set headers, including X-Forwarded-For, X-Real-IP, and X-Forwarded-Host, is affected. If a fronting proxy strips or normalizes those headers but forwards chunked bodies with trailers intact, an attacker can spoof client IP for allow-lists, rate limits, or auditing, forge the https scheme, or inject internal authorization headers. A promoted Connection: close trailer is also honored, allowing attacker-controlled termination of pooled backend connections. This issue is fixed in versions 0.23.18 and 1.0.0-M42.

CVSS v3
7.4
EG Score
7.4(medium)
EG Risk
33(Track)
EG Risk 33/100SSVC: 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
Severity74% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

August 12, 2026

Last Modified

August 13, 2026

Advisory Details (4)

Auto-updated Aug 12, 2026
Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

v1.0.0-M42

Patch available: http4s/blaze v1.0.0-M42 (pre-release)

https://github.com/http4s/blaze/releases/tag/v1.0.0-M42
github_release Patch Available

v0.23.18

Patch available: http4s/blaze v0.23.18

https://github.com/http4s/blaze/releases/tag/v0.23.18
github_commit Patch Available

commit ef3e666c146c (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit ef3e666c146c)

https://github.com/http4s/blaze/commit/ef3e666c146cfc16cb6603f1fc3c464daab4a24f
github Patch Available

Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass) · Advisory · http4s/blaze · GitHub

https://github.com/http4s/blaze/security/advisories/GHSA-46q4-43ph-c6fr

Vendor Advisories for CVE-2026-73495(1)

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

Affected Packages

(3 across 1 ecosystem)
Maven(3)
PackageVulnerable rangeFixed inDependents
org.http4s:blaze-http_2.120.12.10 ... 0.23.17 (56 versions)0.23.18—
org.http4s:blaze-http_2.130.14.10 ... 0.23.17 (27 versions)0.23.18—
org.http4s:blaze-http_30.15.0 ... 0.23.17 (10 versions)0.23.18—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× 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. 2026-08-25 17:13 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 18:48 UTCEG score recompute
  4. 2026-08-23 09:24 UTCEG score recompute
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-21 23:59 UTCEG score recompute
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 01:42 UTCEG score recompute
  9. 2026-08-20 22:56 UTCEPSS rescore
  10. 2026-08-20 03:26 UTCEG score recompute
  11. 2026-08-19 17:04 UTCEPSS rescore
  12. 2026-08-18 17:50 UTCEG score recompute
  13. 2026-08-18 13:49 UTCEPSS rescore
  14. 2026-08-18 13:49 UTCEPSS rescore
  15. 2026-08-17 19:13 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 19:29 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 08:21 UTCEG score recompute
  21. 2026-08-16 02:15 UTCEPSS rescore
  22. 2026-08-15 10:06 UTCEG score recompute
  23. 2026-08-15 01:31 UTCEPSS rescore
  24. 2026-08-14 00:43 UTCEG score recompute
  25. 2026-08-13 22:00 UTCEPSS rescore
Show 5 more
  1. 2026-08-13 13:35 UTCEG score recompute
  2. 2026-08-13 13:18 UTCEG score recompute
  3. 2026-08-12 22:21 UTCEG score recompute
  4. 2026-08-12 21:21 UTCEG score recompute
  5. 2026-08-12 21:20 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-73495?
CVE-2026-73495 is a high vulnerability published on August 12, 2026. blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and 1.0.0-M42, blaze-server can merge HTTP/1.1 chunked-body trailer fields into Request.headers. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject…
When was CVE-2026-73495 disclosed?
CVE-2026-73495 was first published in the National Vulnerability Database on August 12, 2026, with the most recent update on August 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73495 actively exploited?
CVE-2026-73495 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 79.1% of all scored CVEs.
What is the CVSS score of CVE-2026-73495?
CVE-2026-73495 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2026-73495?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73495, 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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