CVE-2026-1525

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 60% of all CVEs by exploit prediction. 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: epss, nvd
Elevated
9.8EG
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
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: 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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
41%
KEV
Not listed

Published

March 12, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Sep 15, 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(13)

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
redhatnodejs:24-9070020260402152654.rhel92026-04-09redhat
redhatnodejs:22-9070020260401095228.rhel92026-04-09redhat
redhatnodejs22-1:22.22.2-2.el10_02026-04-09redhat
redhatnodejs22-1:22.22.2-1.el10_12026-04-08redhat
redhatnodejs:22-8100020260331102257.6d8804032026-04-08redhat

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.

Affected Packages

(3 across 3 ecosystems)
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 7.3.0+dfsg1+~cs24.12.11-2 (7 versions)7.24.5+dfsg+~cs3.2.0-1—
npm(1)
PackageVulnerable rangeFixed inDependents
undici—7.24.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 25× 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. 2026-09-18 19:27 UTCEPSS rescore
  2. 2026-09-16 14:07 UTCEPSS rescore
  3. 2026-09-16 05:14 UTCEPSS rescore
  4. 2026-09-13 16:46 UTCEPSS rescore
  5. 2026-09-12 15:00 UTCEPSS rescore
  6. 2026-09-11 14:52 UTCEPSS rescore
  7. 2026-09-11 09:36 UTCEPSS rescore
  8. 2026-09-10 09:34 UTCEPSS rescore
  9. 2026-09-08 22:00 UTCEPSS rescore
  10. 2026-09-07 16:01 UTCEPSS rescore
  11. 2026-09-06 13:47 UTCEPSS rescore
  12. 2026-09-04 05:06 UTCEPSS rescore
  13. 2026-09-02 19:10 UTCOSV refresh
  14. 2026-09-02 14:11 UTCEPSS rescore
  15. 2026-09-01 13:53 UTCEPSS rescore
  16. 2026-09-01 04:39 UTCEPSS rescore
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-30 01:22 UTCEPSS rescore
  19. 2026-08-28 21:41 UTCEPSS rescore
  20. 2026-08-27 14:25 UTCEPSS rescore
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-25 13:48 UTCEPSS rescore
  23. 2026-08-23 00:19 UTCEPSS rescore
  24. 2026-08-21 23:49 UTCEPSS rescore
  25. 2026-08-20 22:55 UTCEPSS rescore
Show 68 more
  1. 2026-08-19 17:03 UTCEPSS rescore
  2. 2026-08-18 13:48 UTCEPSS rescore
  3. 2026-08-17 13:47 UTCEPSS rescore
  4. 2026-08-16 14:56 UTCEPSS rescore
  5. 2026-08-16 11:41 UTCEG score recompute
  6. 2026-08-16 11:41 UTCVendor advisory
  7. 2026-08-16 02:14 UTCEPSS rescore
  8. 2026-08-15 01:30 UTCEPSS rescore
  9. 2026-08-15 00:54 UTCVendor advisory
  10. 2026-08-14 20:37 UTCVendor advisory
  11. 2026-08-14 16:17 UTCVendor advisory
  12. 2026-08-14 12:00 UTCVendor advisory
  13. 2026-08-14 07:42 UTCEG score recompute
  14. 2026-08-14 07:42 UTCVendor advisory
  15. 2026-08-13 22:00 UTCEPSS rescore
  16. 2026-08-13 03:01 UTCVendor advisory
  17. 2026-08-12 22:44 UTCEG score recompute
  18. 2026-08-12 22:44 UTCVendor advisory
  19. 2026-08-12 13:50 UTCEPSS rescore
  20. 2026-08-12 02:00 UTCVendor advisory
  21. 2026-08-11 21:42 UTCEG score recompute
  22. 2026-08-11 21:42 UTCVendor advisory
  23. 2026-08-11 13:42 UTCEPSS rescore
  24. 2026-08-11 09:08 UTCVendor advisory
  25. 2026-08-11 04:51 UTCEG score recompute
  26. 2026-08-11 04:51 UTCVendor advisory
  27. 2026-08-11 00:00 UTCEPSS rescore
  28. 2026-08-10 12:54 UTCVendor advisory
  29. 2026-08-10 06:38 UTCVendor advisory
  30. 2026-08-10 02:20 UTCVendor advisory
  31. 2026-08-09 22:02 UTCVendor advisory
  32. 2026-08-09 17:44 UTCEG score recompute
  33. 2026-08-09 17:44 UTCVendor advisory
  34. 2026-08-09 13:46 UTCEPSS rescore
  35. 2026-08-09 13:26 UTCVendor advisory
  36. 2026-08-09 07:22 UTCEG score recompute
  37. 2026-08-09 07:22 UTCVendor advisory
  38. 2026-08-08 16:37 UTCEPSS rescore
  39. 2026-08-08 11:27 UTCVendor advisory
  40. 2026-08-08 06:57 UTCVendor advisory
  41. 2026-08-08 02:39 UTCVendor advisory
  42. 2026-08-07 22:21 UTCVendor advisory
  43. 2026-08-07 18:04 UTCEG score recompute
  44. 2026-08-07 18:04 UTCVendor advisory
  45. 2026-08-06 19:48 UTCEG score recompute
  46. 2026-08-06 19:48 UTCVendor advisory
  47. 2026-08-06 13:46 UTCEPSS rescore
  48. 2026-08-06 10:31 UTCVendor advisory
  49. 2026-08-06 06:13 UTCVendor advisory
  50. 2026-08-06 01:55 UTCEG score recompute
  51. 2026-08-06 01:55 UTCVendor advisory
  52. 2026-08-05 19:17 UTCEPSS rescore
  53. 2026-08-04 15:10 UTCEPSS rescore
  54. 2026-08-04 10:38 UTCEPSS rescore
  55. 2026-08-04 05:43 UTCVendor advisory
  56. 2026-08-04 01:12 UTCEG score recompute
  57. 2026-08-04 01:12 UTCVendor advisory
  58. 2026-08-03 10:35 UTCEPSS rescore
  59. 2026-08-03 01:55 UTCVendor advisory
  60. 2026-08-02 21:37 UTCVendor advisory
  61. 2026-08-02 17:20 UTCEG score recompute▲ 3.30
  62. 2026-08-02 17:20 UTCVendor advisory
  63. 2026-08-02 02:26 UTCEPSS rescore
  64. 2026-08-01 04:15 UTCEPSS rescore
  65. 2026-07-30 01:30 UTCEPSS rescore
  66. 2026-07-27 14:13 UTCEPSS rescore
  67. 2026-07-27 12:52 UTCEG score recompute
  68. 2026-07-27 12:52 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-1525?
CVE-2026-1525 is a critical 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 58.6% 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).
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

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