CyberSecBulletin
CVE-2022-46874NVD status: Modified

Firefox: Improper Control of Generation of Code

Published Updated By the CyberSecBulletin desk

CVE-2022-46874 is a high-severity improper control of generation of code vulnerability in Firefox from Mozilla, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 108 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 0.97% chance of exploitation within 30 days, higher than 63% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Firefox to 108 or a later version.
  2. Update Thunderbird to 102.6.1 or 102.6, whichever matches your release line, or a later version.
  3. Update Firefox ESR to 102.6 or a later version.
  4. Read the advisory on 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.
  6. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
MozillaFirefoxbefore 108108
MozillaThunderbirdbefore 102.6.1; before 102.6102.6.1, 102.6
MozillaFirefox ESRbefore 102.6102.6

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
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
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:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighNVD
CVSS 3.18.8HighCISA (ADP)

Official description

A file with a long filename could have had its filename truncated to remove the valid extension, leaving a malicious extension in its place. This could potentially led to user confusion and the execution of malicious code.<br/>*Note*: This issue was originally included in the advisories for Thunderbird 102.6, but a patch (specific to Thunderbird) was omitted, resulting in it actually being fixed in Thunderbird 102.6.1. This vulnerability affects Firefox < 108, Thunderbird < 102.6.1, Thunderbird < 102.6, and Firefox ESR < 102.6.

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

The underlying weakness: Improper Control of Generation of Code

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

How developers prevent this class of flaw

  • Refactor your program so that you do not have to dynamically generate code.
  • Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
  • Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

More Improper Control of Generation of Code vulnerabilities (CWE-94)

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 Improper Control of Generation of Code vulnerabilities

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