CVE-2022-23516 | Uncontrolled Recursion in Loofah

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Loofah >= 2.2.0, < 2.19.1 uses recursion for sanitizing CDATA sections, making it susceptible to stack exhaustion and raising a SystemStackError exception. This may lead to a denial of service through CPU resource consumption. This issue is patched in version 2.19.1. Users who are unable to upgrade may be able to mitigate this vulnerability by limiting the length of the strings that are sanitized.

Published: 2022-12-14 Last update: 2025-11-03 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2022-23516 is rated Low Risk (33/100): CVSS High severity, with low exploitation likelihood (EPSS 0.03%). 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-2022-23516

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 2025-11-21 0.43% 0.03% -0.40%
2 2025-11-18 0.03% 0.43% +0.41%
3 2025-03-30 — 0.03% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-23516

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
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]
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]

Weakness enumeration for CVE-2022-23516

GitHub Security Advisory for CVE-2022-23516

GHSA-3x8r-x6xp-q4vm · Severity: high · Ecosystem: rubygems — Uncontrolled Recursion in Loofah

OS Trackers for CVE-2022-23516

vendor priority summary link
debian not yet assigned CVE-2022-23516 not yet assigned priority: Debian including 1 source packages (ruby-loofah), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2022-23516
redhat medium — https://access.redhat.com/security/cve/CVE-2022-23516
suse high — https://www.suse.com/security/cve/CVE-2022-23516/
ubuntu medium CVE-2022-23516 medium priority: Ubuntu including 1 source packages (ruby-loofah), 13 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 5, needs-triage 4, ignored 3, released 1. https://ubuntu.com/security/CVE-2022-23516

Affected software / configurations for CVE-2022-23516

Vendor Product Version Raw CPE
loofah_project loofah >= 2.2.0, < 2.19.1 cpe:2.3:a:loofah_project:loofah:*:*:*:*:*:ruby:*:*

References for CVE-2022-23516

cvelogic Threat Intelligence