CVE-2022-26485
CVE-2022-26485 is a security flaw in Mozilla Firefox, Mozilla’s web browser. Attackers can run their own code on Mozilla Firefox. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 7 Mar 2022.[1]
Mozilla Firefox is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version 97.0.2, 91.6.1, 97.3.0 and 91.6.2.
Description
CISA calls it an use-after-free in Mozilla Firefox. In its words: “Mozilla Firefox contains a use-after-free vulnerability in XSLT parameter processing which can be exploited to perform arbitrary code execution.”[1]
The CVE record adds: “Removing an XSLT parameter during processing could have lead to an exploitable use-after-free. We have had reports of attacks in the wild abusing this flaw. This vulnerability affects Firefox < 97.0.2, Firefox ESR < 91.6.1, Firefox for Android < 97.3.0, Thunderbird < 91.6.2, and Focus < 97.3.0.”[2]
The underlying weakness is use after free (CWE-416), in MITRE’s list of common software weaknesses.
It scores 8.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Firefox | 97.0.2 |
| Firefox ESR | 91.6.1 |
| Firefox for Android | 97.3.0 |
| Thunderbird | 91.6.2 |
| Focus | 97.3.0 |
Every device with Mozilla Firefox needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 7 Mar 2022. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 21 Mar 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 14%. That’s in the top 4% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Mozilla has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Mozilla Firefox now.Install the latest update from Mozilla on every device that has it, and restart when asked. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on 97.0.2 or later.Fixed in version 97.0.2, 91.6.1, 97.3.0 and 91.6.2. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| The flaw is made public in the National Vulnerability Database, with a severity score of 8.8.[2] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 14%.[4] |
See also
Other Mozilla Firefox flaws
- CVE-2024-9680: use-after-free ·
- CVE-2015-4495: security feature bypass ·
- CVE-2022-26486: use-after-free ·
- CVE-2013-1675: information disclosure ·
Other Mozilla flaws
- CVE-2010-3765, Mozilla products: remote code execution ·
- CVE-2016-9079, Mozilla Firefox, Firefox ESR, and Thunderbird: use-after-free ·
- CVE-2019-11708, Mozilla Firefox and Thunderbird: sandbox escape ·
- CVE-2019-11707, Mozilla Firefox and Thunderbird: type confusion ·
- CVE-2013-1690, Mozilla Firefox and Thunderbird: denial-of-service ·
Other use after free flaws
- CVE-2026-109619, PHP: stale internal request-state ·
- CVE-2026-109618, PHP: memory corruption ·
- CVE-2026-68820, Microsoft Windows Ancillary Function Driver for WinSock: use-after-free ·
- CVE-2010-0249, Microsoft Internet Explorer: use-after-free ·
- CVE-2020-9715, Adobe Acrobat: use-after-free ·
Added the same day
- CVE-2022-26486, Mozilla Firefox: use-after-free ·
- CVE-2021-21973, VMware vCenter Server and Cloud Foundation: server side request forgery (SSRF) ·
- CVE-2020-8218, Pulse Secure Pulse Connect Secure: code injection ·
- CVE-2019-11581, Atlassian Jira Server and Data Center: server-side template injection ·
- CVE-2017-6077, NETGEAR Wireless Router DGN2200: dGN2200 remote code execution ·
Every Mozilla flaw on CISA’s list · Everything added in March 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Mozilla Firefox Use-After-Free Vulnerability”. Known Exploited Vulnerabilities Catalog, added 7 Mar 2022.
- ^ National Institute of Standards and Technology. “CVE-2022-26485 Detail”. National Vulnerability Database, published 22 Dec 2022.
- ^ Mozilla. Advisories and fixes: mozilla.org.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.143, percentile 96.6, 31 Oct 2026.
- CVE Program. “CVE-2022-26485”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.