CVE-2026-73494

HIGHPre-NVD 7.47.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (48th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
7.4EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 7.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42.

CVSS v3
7.4
EG Score
7.4HIGHmedium confidence
EG Risk
34
EG Risk 34/100

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 (value × EchelonGraph’s weight)
Severity74% × 45%
The EG Score, 7.4 of 10.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.6%
EPSS %ILE
48th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 24, 2026

Last Modified

September 30, 2026

Advisory Details (9)

Auto-updated Sep 14, 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 e871ebb1d27f (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit e871ebb1d27f)

https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6
GitHub commit Patch Available

commit c47d9675f876 (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit c47d9675f876)

https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a
GitHub commit Patch Available

commit a54bc9cd3175 (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit a54bc9cd3175)

https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734
GitHub commit Patch Available

commit 927b67753a78 (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit 927b67753a78)

https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3
GitHub commit Patch Available

commit 4eec2007806a (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit 4eec2007806a)

https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96
GitHub commit Patch Available

commit 3f7c022e3066 (http4s/blaze)

Patch available: http4s/blaze v0.23.18 (contains commit 3f7c022e3066)

https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17
GitHub advisoryMentions a patch (unverified)

Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser · Advisory · http4s/blaze · GitHub

https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v

Vendor Advisories for CVE-2026-73494(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 rangeFix by version rangeDependents
org.http4s:blaze-http_2.131.0.0-M33 ... 1.0.0-M41 (9 versions)
  • every version up to 0.23.18: fixed in 0.23.18
  • 1.0.0-M1 up to 1.0.0-M42: fixed in 1.0.0-M42
—
org.http4s:blaze-http_31.0.0-M33 ... 1.0.0-M41 (9 versions)
  • every version up to 0.23.18: fixed in 0.23.18
  • 1.0.0-M1 up to 1.0.0-M42: fixed in 1.0.0-M42
—
org.http4s:http4s-blaze-server_2.130.10.0-M10 ... 0.23.9 (95 versions)
  • every version up to 0.23.18: fixed in 0.23.18
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 43× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-10-13 07:53 UTCEG score recompute
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  5. 2026-10-12 15:40 UTCEG score recompute
  6. 2026-10-11 19:26 UTCEG score recompute
  7. 2026-10-11 16:42 UTCEG score recompute
  8. 2026-10-11 14:01 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  10. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  12. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  13. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  15. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  16. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  17. 2026-10-04 07:41 UTCEG score recompute
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  19. 2026-10-02 19:43 UTCEG score recompute
  20. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  21. 2026-09-30 18:11 UTCEG score recompute
  22. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  23. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  24. 2026-09-28 04:25 UTCEG score recompute
  25. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 47th percentile
Show 19 more
  1. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-09-25 09:59 UTCEG score recompute
  3. 2026-09-23 22:16 UTCEG score recompute
  4. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-09-22 22:09 UTCEG score recompute
  6. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  7. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-09-20 01:39 UTCEG score recompute
  9. 2026-09-18 22:27 UTCEG score recompute
  10. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  11. 2026-09-18 02:56 UTCEG score recompute
  12. 2026-09-17 01:58 UTCEG score recompute
  13. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  14. 2026-09-16 06:38 UTCEG score recompute
  15. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  16. 2026-09-14 20:27 UTCEG score recompute
  17. 2026-09-14 20:16 UTCEG score recompute
  18. 2026-09-14 18:37 UTCEG score recompute
  19. 2026-08-12 21:21 UTCEG score recomputeFirst assessed: 7.4 HIGH

Related CVEs(same product + same CWE)

Same product

3 shown

Maven:org.http4s:blaze-http_2.13 · Maven:org.http4s:http4s-blaze-server_2.13

Frequently asked(5)

What is CVE-2026-73494?
CVE-2026-73494 is a high-severity vulnerability; its CVE record was published on July 24, 2026. blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a…
When was the CVE record for CVE-2026-73494 published?
The CVE record for CVE-2026-73494 was published on July 24, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 30, 2026; the record at its source may have been updated since.
Is CVE-2026-73494 actively exploited?
CVE-2026-73494 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (48th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73494?
CVE-2026-73494 has a CVSS base score of 7.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73494?
A fix for CVE-2026-73494 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-73494 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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