CVE-2023-45143 | Undici's cookie header not cleared on cross-origin redirect in fetch

Undici is an HTTP/1.1 client written from scratch for Node.js. Prior to version 5.26.2, Undici already cleared Authorization headers on cross-origin redirects, but did not clear `Cookie` headers. By design, `cookie` headers are forbidden request headers, disallowing them to be set in RequestInit.headers in browser environments. Since undici handles headers more liberally than the spec, there was a disconnect from the assumptions the spec made, and undici's implementation of fetch. As such this may lead to accidental leakage of cookie to a third-party site or a malicious attacker who can control the redirection target (ie. an open redirector) to leak the cookie to the third party site. This was patched in version 5.26.2. There are no known workarounds.

Published: 2023-10-12 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-45143 is rated Low Risk (25.4/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.10%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-45143

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 0.29% 0.10% -0.18%
2 2026-03-01 0.10% 0.29% +0.18%
3 2026-02-04 0.10%

Full EPSS history (37 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-45143

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.9 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
0.5 3.4 [email protected]
3.5 3.1 LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
2.1 1.4 [email protected]

Weakness enumeration for CVE-2023-45143

GitHub Security Advisory for CVE-2023-45143

GHSA-wqq4-5wpv-mx2g · Severity: low · Ecosystem: npm — Undici's cookie header not cleared on cross-origin redirect in fetch

OS Trackers for CVE-2023-45143

vendor priority summary link
alpine CVE-2023-45143: 3 source package rows (nodejs, nodejs-current, openjdk21); 18 state rows across 13 repos (3.17-main, 3.18-community, 3.18-main, 3.19-community, 3.19-main, 3.20-community, 3.20-main, 3.21-community, 3.21-main, 3.22-community, 3.22-main, edge-community, edge-main); fixed 18, open 0. https://security.alpinelinux.org/vuln/CVE-2023-45143
debian not yet assigned CVE-2023-45143 not yet assigned priority: Debian including 1 source packages (node-undici), 4 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2023-45143
gentoo high CVE-2023-45143: 1 GLSA(s) (202505-11), 1 atom(s) (net-libs/nodejs); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-45143
redhat low https://access.redhat.com/security/cve/CVE-2023-45143
suse low CVE-2023-45143 severity low: SUSE including 74 source package names (16-18.13:nodejs16-16.20.2-150400.3.27.2, 16-18.13:npm16-16.20.2-150400.3.27.2, …), 273 product×package rows across 29 product lines (Container bci/node, Container bci/nodejs, … (29 product lines)): Known Not Affected 158, Fixed 115. https://www.suse.com/security/cve/CVE-2023-45143/
ubuntu medium CVE-2023-45143 medium priority: Ubuntu including 1 source packages (node-undici), 12 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 5, not-affected 3, ignored 2, needs-triage 1, released 1. https://ubuntu.com/security/CVE-2023-45143

Affected software / configurations for CVE-2023-45143

Vendor Product Version Raw CPE
nodejs undici < 5.26.2 cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*
fedoraproject fedora 37 cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
fedoraproject fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*

References for CVE-2023-45143

URL Tags
https://github.com/nodejs/undici/commit/e041de359221ebeae04c469e8aff4145764e6d76 Patch
https://github.com/nodejs/undici/releases/tag/v5.26.2 Release Notes
https://github.com/nodejs/undici/security/advisories/GHSA-q768-x9m6-m9qp Not Applicable
https://github.com/nodejs/undici/security/advisories/GHSA-wqq4-5wpv-mx2g Vendor Advisory
https://hackerone.com/reports/2166948 Permissions Required
https://lists.fedoraproject.org/archives/list/[email protected]/message/3N4NJ7FR4X4FPZUGNTQAPSTVB2HB2Y4A/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/E72T67UPDRXHIDLO3OROR25YAMN4GGW5/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/FNA62Q767CFAFHBCDKYNPBMZWB7TWYVU/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/HT7T2R4MQKLIF4ODV4BDLPARWFPCJ5CZ/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/LKYHSZQFDNR7RSA7LHVLLIAQMVYCUGBG/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/X6QXN4ORIVF6XBW4WWFE7VNPVC74S45Y/ Mailing List Third Party Advisory
cvelogic Threat Intelligence