CVE-2026-63344

HIGHPre-NVD 8.68.6
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (29th 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
Elevated

Also known asEUVD-2026-114539 (ENISA EUVD)Source: ENISA EUVD

8.6EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.6Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of requestBody/responses are emitted verbatim into a Refit [Headers("Accept: ", "Content-Type: ")] attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without --skip-validation, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A [ModuleInitializer] method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.

CVSS
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
55
EG Risk 55/100

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)
Severity86% × 45%
Impact severity (EG Severity): CVSS 8.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
29th
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 (8.6): severity, escalated by confirmed exploitation. This CVE's 8.6 is its impact severity (EG Severity), not escalated.

EG Severity
8.6 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (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.

The score's inputs: 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

October 30, 2026

Last Modified

November 6, 2026

Advisory Details (7)

Auto-updated Oct 30, 2026
Patch available. Sources: github_commit, github_release, github, github_pr.
GitHub release Patch Available

v2.1.2

Patch available: christianhelle/refitter 2.1.2

https://github.com/christianhelle/refitter/releases/tag/2.1.2
GitHub commit Patch Available

commit ab4d8e439d6f (christianhelle/refitter)

Patch available: christianhelle/refitter 2.1.2 (contains commit ab4d8e439d6f)

https://github.com/christianhelle/refitter/commit/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67
GitHub pull request Patch Available

Fix RCE attribute injection in generated Refit clients (GHSA-3fhm-p725-h3g3, GHSA-58x9-vjvp-6mx8, GHSA-p32v-8v8j-j534)

Patch available: christianhelle/refitter 2.1.2 (PR #1178 merged 2026-07-27)

https://github.com/christianhelle/refitter/pull/1178
GitHub advisoryMentions a patch (unverified)

RCE via content-type key (content map key in requestBody/responses) -> unescaped [Headers("Accept: <ct>", "Content-Type: <ct>")] Refit attribute -> [ModuleInitializer] at assembly load · Advisory · christianhelle/refitter · GitHub

https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 15× 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 its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS → 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-13 16:53 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  4. 2026-11-11 03:55 UTCEchelonGraph re-scored
  5. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  6. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  7. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  8. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  9. 2026-11-06 19:26 UTCEchelonGraph re-scored
  10. 2026-11-06 18:52 UTCEchelonGraph re-scored
  11. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  12. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  13. 2026-11-03 20:19 UTCEchelonGraph re-scored
  14. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  15. 2026-11-02 19:46 UTCEchelonGraph re-scored
  16. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  17. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  18. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  19. 2026-10-31 00:02 UTCENISA EUVD ID recordedEUVD-2026-114539 · Source: ENISA EUVD
  20. 2026-10-30 23:26 UTCEchelonGraph re-scored
  21. 2026-10-30 22:24 UTCEchelonGraph re-scoredFirst assessed: 8.6 HIGH
  22. 2026-10-30 22:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-63344?
CVE-2026-63344 is a high-severity vulnerability; its CVE record was published on October 30, 2026. Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of requestBody/responses are emitted verbatim into a Refit [Headers("Accept: <ct>", "Content-Type: <ct>")] attribute string without escaping quotation marks. A…
When was the CVE record for CVE-2026-63344 published?
The CVE record for CVE-2026-63344 was published on October 30, 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 November 6, 2026; the record at its source may have been updated since.
Is CVE-2026-63344 actively exploited?
CVE-2026-63344 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (29th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63344?
CVE-2026-63344 has a CVSS base score of 8.6 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-63344?
A fix for CVE-2026-63344 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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