CyberSecBulletin
CVE-2024-11702NVD status: Analyzed

Firefox: Inappropriate Encoding for Output Context

Published Updated By the CyberSecBulletin desk

CVE-2024-11702 is a high-severity inappropriate encoding for output context vulnerability in Firefox from Mozilla, with a CVSS 3.1 base score of 7.5 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 133 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 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Firefox to 133 or a later version.
  2. Update Thunderbird to 133 or a later version.
  3. Read the advisory on mozilla.org for workarounds and exact fixed builds.
  4. 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 133133
MozillaThunderbirdbefore 133133

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
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
NoneNothing can be modified.
Availability
NoneAvailability is not affected.

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

Official description

Copying sensitive information from Private Browsing tabs on Android, such as passwords, may have inadvertently stored data in the cloud-based clipboard history if enabled. This vulnerability affects Firefox < 133 and Thunderbird < 133.

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

The underlying weakness: Inappropriate Encoding for Output Context

The product uses or specifies an encoding when generating output to a downstream component, but the specified encoding is not the same as the encoding that is expected by the downstream component.

How developers prevent this class of flaw

  • Use context-aware encoding. That is, understand which encoding is being used by the downstream component, and ensure that this encoding is used. If an encoding can be specified, do so, instead of assuming that the default encoding is the same as the default being assumed by the downstream component.
  • Where possible, use communications protocols or data formats that provide strict boundaries between control and data. If this is not feasible, ensure that the protocols or formats allow the communicating components to explicitly state which encoding/decoding method is being used. Some template frameworks provide built-in support.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using the ESAPI Encoding control or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error. Note that some template mechanisms provide built-in support for the appropriate encoding.

More Inappropriate Encoding for Output Context vulnerabilities (CWE-838)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other references

Other vulnerabilities in Firefox

All Firefox vulnerabilities

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