CVE-2026-22036 [Medium] | Security Vulnerability in Undici

Undici is an HTTP/1.1 client for Node.js. Prior to 7.18.0 and 6.23.0, the number of links in the decompression chain is unbounded and the default maxHeaderSize allows a malicious server to insert thousands compression steps leading to high CPU usage and excessive memory allocation. This vulnerability is fixed in 7.18.0 and 6.23.0.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-01-23	0.05%	0.02%	-0.03%
2	2026-01-20	0.04%	0.05%	+0.01%
3	2026-01-15	—	0.04%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-01-23

0.05%

0.02%

-0.03%

2026-01-20

0.04%

0.05%

+0.01%

2026-01-15

—

0.04%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.9	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H` 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:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.2	3.6	[email protected]
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` 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:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.9

3.1

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H 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:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.2

3.6

[email protected]

7.5

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 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:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

3.6

[email protected]

GitHub Security Advisory for CVE-2026-22036

GHSA-g9mf-h72j-4rw9 · Severity: medium · Ecosystem: npm — Undici has an unbounded decompression chain in HTTP responses on Node.js Fetch API via Content-Encoding leads to resource exhaustion

OS Trackers for CVE-2026-22036

vendor	priority	summary	link
`alpine`	—	CVE-2026-22036: 1 source package rows (nodejs); 10 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 10.	https://security.alpinelinux.org/vuln/CVE-2026-22036
`debian`	not yet assigned	CVE-2026-22036 not yet assigned priority: Debian including 1 source packages (node-undici), 4 status rows across 4 suites (bookworm, forky, sid, trixie): open 2, resolved 2.	https://security-tracker.debian.org/tracker/CVE-2026-22036
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2026-22036
`suse`	medium	CVE-2026-22036 severity moderate: SUSE including 58 source package names (2.1.3-6.15:qemu-guest-agent-8.2.9-1.1, corepack20-20.20.0-150600.3.15.1, …), 205 product×package rows across 35 product lines (Container suse/sl-micro/6.0/kvm-os-container, Image SL-Micro, … (35 product lines)): Fixed 128, Known Not Affected 72, First Fixed 5.	https://www.suse.com/security/cve/CVE-2026-22036/
`ubuntu`	medium	CVE-2026-22036 medium priority: Ubuntu including 1 source packages (node-undici), 5 status rows across 5 suites (jammy, noble, plucky, questing, upstream): needs-triage 3, DNE 1, ignored 1.	https://ubuntu.com/security/CVE-2026-22036

Affected software / configurations for CVE-2026-22036

Vendor	Product	Version	Raw CPE
nodejs	undici	< 6.23.0	cpe:2.3:a:nodejs:undici::::::node.js::*
nodejs	undici	>= 7.0.0, < 7.18.2	cpe:2.3:a:nodejs:undici::::::node.js::*

References for CVE-2026-22036

URL	Tags
https://github.com/nodejs/undici/commit/b04e3cbb569c1596f86c108e9b52c79d8475dcb3	Patch
https://github.com/nodejs/undici/security/advisories/GHSA-g9mf-h72j-4rw9	Vendor Advisory

URL

CVE-2026-22036 | Undici has an unbounded decompression chain in HTTP responses on Node.js Fetch API via Content-Encoding leads to resource exhaustion

Exploit prediction scoring system (EPSS) score for CVE-2026-22036

Common vulnerability scoring system (CVSS) metrics for CVE-2026-22036

Weakness enumeration for CVE-2026-22036

GitHub Security Advisory for CVE-2026-22036

OS Trackers for CVE-2026-22036

Affected software / configurations for CVE-2026-22036

References for CVE-2026-22036