No exploitation reportedFix available

CVE-2022-31736

Q: Is CVE-2022-31736 actively exploited?

Active exploitation of CVE-2022-31736 has not been confirmed. Its EPSS score was 1.1% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2022-31736?

CVE-2022-31736 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2022-12-22
Fixed in101
WeaknessCWE-942

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A malicious website could have learned the size of a cross-origin resource that supported Range requests. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.

Timeline

dates in UTC

2022-12-2220:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2022-31736?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2022-31736?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Mozilla firefox

Branch	Affected	Fixed in	Source
101.x	< 101	101	NVD

Mozilla firefox esr

Branch	Affected	Fixed in	Source
91.10	< 91.10	91.10	NVD

Mozilla thunderbird

Branch	Affected	Fixed in	Source
91.10	< 91.10	91.10	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Mozilla firefox to 101

Advisories and patches

bugzilla.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2025-04-15
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.19.82025-04-15
NVDCVSS 3.19.8read 2026-10-23
CISA-ADPweakness (CWE)CWE-9422025-04-15
FIRST EPSSEPSS score1.1 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2022-12-22
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2022-31736?

A malicious website could have learned the size of a cross-origin resource that supported Range requests. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.

Is CVE-2022-31736 actively exploited?

Active exploitation of CVE-2022-31736 has not been confirmed. Its EPSS score was 1.1% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2022-31736?

CVE-2022-31736 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Hear about the next vulnerability in your software

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database