CVE-2022-23959

In Varnish Cache before 6.6.2 and 7.x before 7.0.2, Varnish Cache 6.0 LTS before 6.0.10, and and Varnish Enterprise (Cache Plus) 4.1.x before 4.1.11r6 and 6.0.x before 6.0.9r4, request smuggling can occur for HTTP/1 connections.

Published: 2022-01-25 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2022-23959 is rated Moderate Risk (63.7/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.96%). Review affected assets and schedule remediation.

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-2022-23959

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 2026-06-23 1.88% 1.96% +0.08%
2 2026-06-15 0.35% 1.88% +1.53%
3 2025-12-24 — 0.35% —

Full EPSS history (23 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-23959

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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: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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2022-23959

OS Trackers for CVE-2022-23959

vendor priority summary link
alpine critical CVE-2022-23959: 1 source package rows (varnish); 8 state rows across 8 repos (3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 8, open 0. https://security.alpinelinux.org/vuln/CVE-2022-23959
debian not yet assigned CVE-2022-23959 not yet assigned priority: Debian including 1 source packages (varnish), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2022-23959
redhat high — https://access.redhat.com/security/cve/CVE-2022-23959
suse high CVE-2022-23959 severity important: SUSE including 13 source package names (libvarnishapi3-7.1.0-1.1, libvarnishapi3-7.1.0-bp153.2.3.1, …), 19 product×package rows across 6 product lines (SUSE Liberty Linux 8, SUSE Package Hub 15 SP3, … (6 product lines)): Fixed 19. https://www.suse.com/security/cve/CVE-2022-23959/
ubuntu medium CVE-2022-23959 medium priority: Ubuntu including 1 source packages (varnish), 14 status rows across 14 suites (bionic, focal, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 5, needs-triage 5, released 4. https://ubuntu.com/security/CVE-2022-23959

Affected software / configurations for CVE-2022-23959

Vendor Product Version Raw CPE
varnish-software varnich_cache >= 1.0.0, < 6.6.2 cpe:2.3:a:varnish-software:varnich_cache:*:*:*:*:-:*:*:*
varnish-software varnich_cache >= 4.1.1, < 4.1.11r6 cpe:2.3:a:varnish-software:varnich_cache:*:*:*:*:plus:*:*:*
varnish-software varnich_cache 4.1 cpe:2.3:a:varnish-software:varnich_cache:4.1:*:*:*:lts:*:*:*
varnish-software varnish_cache >= 6.0.0, < 6.0.10 cpe:2.3:a:varnish-software:varnish_cache:*:*:*:*:lts:*:*:*
varnish-software varnish_cache_plus >= 6.0.0, < 6.0.9r4 cpe:2.3:a:varnish-software:varnish_cache_plus:*:*:*:*:*:*:*:*
varnish_cache_project varnish_cache >= 7.0.0, < 7.0.2 cpe:2.3:a:varnish_cache_project:varnish_cache:*:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2022-23959

cvelogic Threat Intelligence