CVE-2026-1525

MEDIUMNVD 9.86.5
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 6.5 under the CNA's CVSS (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: cna:openjs
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: Elevated riskExposed: 0

A fix is available — apply it.

Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire.

Who is impacted:

* Applications using undici.request(), undici.Client, or similar low-level APIs with headers passed as flat arrays * Applications that accept user-controlled header names without case-normalization

Potential consequences:

* Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate Content-Length headers (400 Bad Request) * HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking

CVSS v3
9.8
EG Score
6.5(low)
EG Risk
44(Attend)
EG Risk 44/100SSVC: Attend

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
Severity65% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
39%
KEV
Not listed

Published

March 12, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Jul 27, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: github.
generic

RFC 9110: HTTP Semantics

https://www.rfc-editor.org/rfc/rfc9110.html#section-8.6
github Patch Available

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in undici · Advisory · nodejs/undici · GitHub

https://github.com/nodejs/undici/security/advisories/GHSA-2mjp-6q6p-2qxm
generic🔴 Active Exploitation

CWE - CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (4.20)

https://cwe.mitre.org/data/definitions/444.html
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html

Vendor Advisories for CVE-2026-1525(12)

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

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdevspaces/code-rhel9:17798145922026-05-28redhat
redhatcryostat/cryostat-rhel9:4.2.0-92026-05-26redhat
redhatrhdh/rhdh-hub-rhel9:17779032622026-05-05redhat
redhatrhdh/rhdh-hub-rhel9:17767842862026-04-22redhat
redhatnodejs:22-9060020260409121057.rhel92026-04-14redhat
redhatnodejs24-1:24.14.1-2.el10_12026-04-13redhat
redhatnodejs:24-8100020260408131901.6d8804032026-04-13redhat
redhatnodejs22-1:22.22.2-2.el10_02026-04-09redhat
redhatnodejs:24-9070020260402152654.rhel92026-04-09redhat
redhatnodejs:22-9070020260401095228.rhel92026-04-09redhat
redhatnodejs:22-8100020260331102257.6d8804032026-04-08redhat
redhatnodejs22-1:22.22.2-1.el10_12026-04-08redhat

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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 3× in last 7d / 3× 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. 2026-07-27 14:13 UTCEPSS rescore
  2. 2026-07-27 12:52 UTCEG score recompute
  3. 2026-07-27 12:52 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-1525?
CVE-2026-1525 is a medium vulnerability published on March 12, 2026. Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire. Who is impacted: Applications using…
When was CVE-2026-1525 disclosed?
CVE-2026-1525 was first published in the National Vulnerability Database on March 12, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-1525 actively exploited?
CVE-2026-1525 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 60.5% of all scored CVEs.
What is the CVSS score of CVE-2026-1525?
CVE-2026-1525 has a CVSS v3 base score of 9.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 6.5. The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-1525?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-1525, 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-2026-1525

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