Mozilla Firefox up to 140.13/153/153.0 memory corruption

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$5k-$25k0.85+

Summaryinfo

A vulnerability classified as critical has been found in Mozilla Firefox up to 140.13/153/153.0. Affected is an unknown function. This manipulation causes memory corruption. This vulnerability is handled as CVE-2026-74987. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 140.13/153/153.0 and classified as critical. Affected by this vulnerability is some unknown processing. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Internally found bugs present in Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.

The advisory is shared at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-74987 since 08/17/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/18/2026).

Upgrading to version 140.14, 153.1 or 154 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 140.14/153.1/154

Timelineinfo

08/17/2026 CVE reserved
08/18/2026 +1 days Advisory disclosed
08/18/2026 +0 days VulDB entry created
08/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-74987 (🔒)
GCVE (CVE): GCVE-0-2026-74987
GCVE (VulDB): GCVE-100-391621

Entryinfo

Created: 08/18/2026 15:25
Changes: 08/18/2026 15:25 (56)
Complete: 🔍
Cache ID: 216::103

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