CyberSecBulletin
CVE-2024-2607NVD status: Analyzed

Firefox: Write-what-where Condition

Published Updated By the CyberSecBulletin desk

CVE-2024-2607 is a high-severity write-what-where condition vulnerability in Firefox from Mozilla, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 124 as the first without the flaw, so updating Firefox to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.11% chance of exploitation within 30 days, higher than 66% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Firefox to 124 or a later version.
  2. Update Firefox ESR to 115.9 or a later version.
  3. Update Thunderbird to 115.9 or a later version.
  4. Read the advisory on bugzilla.mozilla.org for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MozillaFirefoxbefore 124124
MozillaFirefox ESRbefore 115.9115.9
MozillaThunderbirdbefore 115.9115.9
DebianDebian Linux10.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).

Official description

Return registers were overwritten which could have allowed an attacker to execute arbitrary code. *Note:* This issue only affected Armv7-A systems. Other operating systems are unaffected. This vulnerability affects Firefox < 124, Firefox ESR < 115.9, and Thunderbird < 115.9.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Write-what-where Condition

Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.
  • Use OS-level preventative functionality integrated after the fact. Not a complete solution.

More Write-what-where Condition vulnerabilities (CWE-123)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Firefox

All Firefox vulnerabilities

Recent Write-what-where Condition vulnerabilities

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