http4k is a functional toolkit for Kotlin HTTP applications. Prior to 4.51.0.0, 5.42.0.0, and 6.49.0.0, ServerFilters.GZip, RequestFilters.GunZip, and the underlying Gzip request-body decompression functions impose no limit on decompressed size. An unauthenticated client can send a small gzip-encoded request body that expands to gigabytes, exhausting the JVM heap and denying service to other clients. The fix uses SizeLimitedInputStream to enforce a default 10 MiB limit, causes ServerFilters.GZip and RequestFilters.GunZip to return 413 Request Entity Too Large, and causes other decompression paths to throw SizeLimitExceededException. This issue is fixed in versions 4.51.0.0, 5.42.0.0, and 6.49.0.0.
CVE-2026-53659
“—” beside the score: it is equal to the CVSS score beside it.
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-17. A secondary CVSS source baseline 7.5; sources differ by 0.0.
Also known asEUVD-2026-77694 (ENISA EUVD) · GHSA-g4w2-6h2r-3m3w (GitHub Security Advisories)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 49EG Risk 49/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.6% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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 at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.6%
- EPSS %ILE
- 50th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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
August 17, 2026
Last Modified
September 30, 2026
Advisory Details (4)
Auto-updated Sep 14, 20266.49.0.0
Patch available: http4k/http4k 6.49.0.0
https://github.com/http4k/http4k/releases/tag/6.49.0.0commit 9f9e02f8efbb (http4k/http4k)
Patch available: http4k/http4k 6.49.0.0 (contains commit 9f9e02f8efbb)
https://github.com/http4k/http4k/commit/9f9e02f8efbbe04e0c70f1c46eef5d9d9067ea5bcommit 2618fe08f980 (http4k/http4k)
Patch available: http4k/http4k 6.38.0.0 (contains commit 2618fe08f980)
https://github.com/http4k/http4k/commit/2618fe08f9801353012561ae1f1382fa2d37bac9Unbounded gzip decompression in `ServerFilters.GZip` / `RequestFilters.GunZip` allowed memory-exhaustion DoS · Advisory · http4k/http4k · GitHub
https://github.com/http4k/http4k/security/advisories/GHSA-g4w2-6h2r-3m3wVendor Advisories for CVE-2026-53659(1)
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 / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| maven | org.http4k:http4k-core @ 5.42.0.0 (fixes >= 5.0.0.0, < 5.42.0.0) | — | ghsa |
| maven | org.http4k:http4k-core | — | ghsa |
| maven | org.http4k:http4k-core @ 6.49.0.0 (fixes >= 6.0.0.0, < 6.49.0.0) | — | ghsa |
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
(1 across 1 ecosystem)
Maven(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| org.http4k:http4k-core | 0.21.0 ... v6.4.1.0 (607 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 45× 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.
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.6% · 50th percentile
- 2026-11-01 07:45 UTCGHSA enrichmentGHSA-g4w2-6h2r-3m3w · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-11-01 07:45 UTCEG score recompute
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 50th percentile
- 2026-10-30 22:03 UTCEG score recompute
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 50th percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 50th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 50th percentile
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-25 14:20 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-24 03:15 UTCEG score recompute
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-18 03:31 UTCEG score recompute
- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-17 08:27 UTCEG score recompute
- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 49th percentile
Show 52 moreShow fewer
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-12 15:57 UTCEG score recompute
- 2026-10-11 19:40 UTCEG score recompute
- 2026-10-11 16:55 UTCEG score recompute
- 2026-10-11 14:18 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-06 21:43 UTCEG score recompute
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-06 09:00 UTCEG score recompute
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-05 09:38 UTCEG score recompute
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-03 17:45 UTCEG score recompute
- 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-03 03:28 UTCEG score recompute
- 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-02 01:33 UTCEG score recompute
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-30 20:04 UTCEG score recompute
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-30 09:56 UTCEG score recompute
- 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-28 21:58 UTCEG score recompute
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-27 21:37 UTCEG score recompute
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-27 08:04 UTCEG score recompute
- 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-25 01:51 UTCEG score recompute
- 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-09-23 23:31 UTCEG score recompute
- 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-09-22 23:47 UTCEG score recompute
- 2026-09-21 23:59 UTCEG score recompute
- 2026-09-21 00:25 UTCEG score recompute
- 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-09-19 23:44 UTCEG score recompute
- 2026-09-18 23:51 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-09-18 00:17 UTCEG score recompute
- 2026-09-16 23:01 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-09-16 06:56 UTCEG score recompute
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 37th percentile
- 2026-09-14 18:35 UTCEG score recompute
- 2026-08-17 22:02 UTCEG score recomputeFirst assessed: 7.5 HIGH
Related CVEs(same product + same CWE)
Same product
2 shownMaven:org.http4k:http4k-core
Frequently asked(5)
What is CVE-2026-53659?
When was the CVE record for CVE-2026-53659 published?
Is CVE-2026-53659 actively exploited?
What is the CVSS score of CVE-2026-53659?
How do I remediate CVE-2026-53659?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53659
Is Your Infrastructure Affected by CVE-2026-53659?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.