CVE-2022-31744Public exploitNetwork attack vector

Content Security Policy bypass via reflected URI query

Published Dec 22, 2022 · Updated Apr 15, 2025

CSS injection in affected Mozilla Firefox and Thunderbird releases allows remote attackers to bypass a page's Content Security Policy. The JAR channel honors a caller-supplied text/css hint over the directory response type, so an internal chrome: or resource: directory listing reflects query text that the stylesheet loader parses as CSS. A victim must load attacker-controlled stylesheet markup; the result is unauthorized page-style modification despite the site's CSP, not script execution.

CVSS severity6.5
Medium
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSS injection in affected Mozilla Firefox and Thunderbird releases allows remote attackers to bypass a page's Content Security Policy. The JAR channel honors a caller-supplied text/css hint over the directory response type, so an internal chrome: or resource: directory listing reflects query text that the stylesheet loader parses as CSS. A victim must load attacker-controlled stylesheet markup; the result is unauthorized page-style modification despite the site's CSP, not script execution.

The record

CVE
CVE-2022-31744
Published
Dec 22, 2022
Updated
Apr 15, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <101

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <101
Mozilla · Thunderbirdversion=unspecified <102; version=unspecified <91.11
Mozilla · Firefox ESRversion=unspecified <91.11

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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