CVE-2026-2766Disclosure(mozilla / firefox)

LOWCVSS 9.8 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

Patch mozilla firefox systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

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0.5/ 10 priority

Sources & remediation

Vendor / third-party advisories

Other references

Weakness type (CWE)

CWE-416

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

firefox
thunderbird

Threat summary

Patch or workaround signal is available
5 mentions across 4 observed days
Momentum state: stable

What's happening

Patch or workaround mentioned in 1 signal
Technical details provided in 5 signals
Disclosure: 4 classified signals
Peaked 3d ago at 2 mentions (2026-02-25); latest day: 1
5 total mentions across 4 days

Affected systems

Vendors

mozilla

Products

firefoxthunderbird

Deep dive

Activity timeline5 mentions / 4d

Signal classification2 categories

Disclosure

480.0%

Patch

120.0%

Referenced assets3 URLs

By indicator

Classification over time

Date	Total	Labels

2026-02-25	2	Disclosure2
2026-02-28	1	Disclosure1
2026-03-01	1	Disclosure1
2026-04-16	1	Patch1

Full discourse5 posts

CVE@CVEnew226d
Disclosure
CVE-2026-2766 Use-after-free in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 148 and Firefox ESR < 140.8. https://www.cve.org/CVERecord?id=CVE-2026-2766
Post summary
CVE-2026-2766 is a use‑after‑free vulnerability in Firefox’s JavaScript JIT engine affecting versions below 148 and ESR below 140.8, with no PoC, exploit, or patch mentioned.
000201.1K
56.6K followersView on X
CRAC Learning - Tech@cracbot224d
Disclosure
CVE-2026-2766 (CVSS:9.8, CRITICAL) is Modified. Use-after-free in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, T..https://nvd.nist.gov/vuln/detail/CVE-2026-2766 #cybersecurityawareness #cybersecurity #CVE #infosec #hacker #nvd #mitre
Post summary
The post discloses a critical use‑after‑free vulnerability (CVSS 9.8) in Firefox’s JavaScript Engine JIT, affecting versions below 148 and ESR below 140.8.
0001046
173 followersView on X
Giuseppe Paternicola@giuseppe_1337177d
Patch
🚨 CRITICAL: CVE-2026-2766 (CVSS 9.8) - Use-after-free in Firefox/Thunderbird JavaScript JIT engine. Network exploitable, no user interaction required. Patch NOW to Firefox 148, ESR 140.8, Thunderbird 148/140.8. #CVE #PatchNow #ThreatIntel https://t.co/S3IZLa4xeK
Post summary
The tweet announces a critical use‑after‑free vulnerability in Firefox/Thunderbird’s JavaScript JIT engine (CVE‑2026‑2766) and urges immediate patching; no PoC, exploit code, or active exploitation claims are provided.
0000036
25 followersView on X
CRAC Learning - Tech@cracbot223d
Disclosure
CVE-2026-2766 (CVSS:9.8, CRITICAL) is Modified. Use-after-free in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, T..https://nvd.nist.gov/vuln/detail/CVE-2026-2766 #cybersecurityawareness #cybersecurity #CVE #infosec #hacker #nvd #mitre
Post summary
The post announces CVE-2026-2766, a critical use‑after‑free flaw in Firefox’s JavaScript JIT engine affecting versions below 148 and ESR below 140.8, without mentioning any PoC, exploit, or patch.
0000029
173 followersView on X
Infoflowcloud@infoflowcloud226d
Disclosure
🚨*CVE* CVE-2026-2766 Use-after-free in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 148 and Firefox ESR < 140.8. https://www.cve.org/CVERecord?id=CVE-2026-2766 ----- Traducción: CVE-2026-2766 Uso después de liberación en el motor JavaScript: co… http://infoflow.cloud`
Post summary
The post announces CVE-2026-2766, a use‑after‑free flaw in Firefox’s JavaScript JIT engine affecting versions below 148 and ESR below 140.8, with no PoC, exploit, or patch details provided.
0000053
54 followersView on X

CPE platform detail4 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

4 of 4 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	mozilla	firefox	-	-	-
App	mozilla	firefox	-	-	-
App	mozilla	thunderbird	-	-	-
App	mozilla	thunderbird	-	-	-

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What researchers are saying

CVE-2026-2766

Giuseppe Paternicola[verified]@giuseppe_1337Patch

The tweet announces a critical use‑after‑free vulnerability in Firefox/Thunderbird’s JavaScript JIT engine (CVE‑2026‑2766) and urges immediate patching; no PoC, exploit code, or active exploitation claims are provided.

CVE@CVEnewDisclosure

CVE-2026-2766 is a use‑after‑free vulnerability in Firefox’s JavaScript JIT engine affecting versions below 148 and ESR below 140.8, with no PoC, exploit, or patch mentioned.

CRAC Learning - Tech@cracbotDisclosure

The post discloses a critical use‑after‑free vulnerability (CVSS 9.8) in Firefox’s JavaScript Engine JIT, affecting versions below 148 and ESR below 140.8.

CRAC Learning - Tech@cracbotDisclosure

The post announces CVE-2026-2766, a critical use‑after‑free flaw in Firefox’s JavaScript JIT engine affecting versions below 148 and ESR below 140.8, without mentioning any PoC, exploit, or patch.

Infoflowcloud@infoflowcloudDisclosure

The post announces CVE-2026-2766, a use‑after‑free flaw in Firefox’s JavaScript JIT engine affecting versions below 148 and ESR below 140.8, with no PoC, exploit, or patch details provided.