http-cache-semantics through 4.2.0 contains a cache validation vulnerability in the _varyMatches() function that fails to properly validate Vary header wildcards due to byte-for-byte string comparison. Attackers can request URLs previously fetched by other clients to receive cached responses intended for different users, disclosing sensitive information across clients.
CVE-2026-93750
MEDIUMPre-NVD 5.95.9Elevated
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 5.9Exploit: Elevated riskExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.9
- EG Score
- 5.9(low)
- EG Risk
- 43(Track)EG Risk 43/100SSVC: 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 computedSeverity59% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
September 18, 2026
Last Modified
September 18, 2026
Advisory Details (4)
Auto-updated Sep 18, 2026🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available
Security Advisory: `Vary: *` reuse prohibition bypassed by whitespace/list forms and prototype field names · Issue #57 · kornelski/http-cache-semantics · GitHub
https://github.com/kornelski/http-cache-semantics/issues/57generic
http-cache-semantics through 4.2.0 Cross-Client Cache Disclosure via Vary Wildcard | Advisories | VulnCheck
https://www.vulncheck.com/advisories/http-cache-semantics-through-4.2.0-cross-client-cache-disclosure-via-vary-wildcardgeneric
http-cache-semantics/index.js at f01112e954b83cfa8765b633ba880e5e980aa54c · kornelski/http-cache-semantics · GitHub
https://github.com/kornelski/http-cache-semantics/blob/f01112e954b83cfa8765b633ba880e5e980aa54c/index.js#L483-L501generic
GitHub - kornelski/http-cache-semantics: RFC 7234 in JavaScript. Parses HTTP headers to correctly compute cacheability of responses, even in complex cases · GitHub
https://github.com/kornelski/http-cache-semanticsVendor Advisories for CVE-2026-93750(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 4× in last 7d / 4× 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.
- 2026-09-18 18:27 UTCEG score recompute
- 2026-09-18 18:14 UTCEG score recompute
- 2026-09-18 17:54 UTCEG score recompute
- 2026-09-18 17:54 UTCMITRE cvelistV5first tracked
Frequently asked(4)
What is CVE-2026-93750?
CVE-2026-93750 is a medium vulnerability published on September 18, 2026. http-cache-semantics through 4.2.0 contains a cache validation vulnerability in the _varyMatches() function that fails to properly validate Vary header wildcards due to byte-for-byte string comparison. Attackers can request URLs previously fetched by other clients to receive cached responses…
When was CVE-2026-93750 disclosed?
CVE-2026-93750 was first published in the National Vulnerability Database on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-93750?
CVE-2026-93750 has a CVSS v3 base score of 5.9 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-93750?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-93750, 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
Explore the affected products and dependency analysis for CVE-2026-93750
Is Your Infrastructure Affected by CVE-2026-93750?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.