CyberSecBulletin
CVE-2023-4576NVD status: Modified

Firefox: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2023-4576 is a high-severity integer overflow or wraparound vulnerability in Firefox from Mozilla, with a CVSS 3.1 base score of 8.6 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 117 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 0.82% chance of exploitation within 30 days, higher than 58% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Firefox to 117 or a later version.
  2. Update Firefox ESR to 102.15 or 115.2, whichever matches your release line, or a later version.
  3. Update Thunderbird to 102.15 or 115.2, whichever matches your release line, 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.

Affected products and versions

VendorProductAffected versionsFixed in
MozillaFirefoxbefore 117117
MozillaFirefox ESRbefore 102.15; before 115.2102.15, 115.2
MozillaThunderbirdbefore 102.15; before 115.2102.15, 115.2

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
ChangedThe attack can reach beyond the vulnerable component into other systems.
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:C/C:H/I:N/A:N. Scored by NVD.

Official description

On Windows, an integer overflow could occur in `RecordedSourceSurfaceCreation` which resulted in a heap buffer overflow potentially leaking sensitive data that could have led to a sandbox escape. *This bug only affects Firefox on Windows. Other operating systems are unaffected.* This vulnerability affects Firefox < 117, Firefox ESR < 102.15, Firefox ESR < 115.2, Thunderbird < 102.15, and Thunderbird < 115.2.

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

The underlying weakness: Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How developers prevent this class of flaw

  • Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

More Integer Overflow or Wraparound vulnerabilities (CWE-190)

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

Recent Integer Overflow or Wraparound vulnerabilities

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