CVE-2023-32206Network attack vector

Application crash via RLBox Expat out-of-bounds read

Published Jun 2, 2023 · Updated May 27, 2025

An out-of-bounds read in Mozilla's RLBox Expat driver allows attackers to crash Firefox before 113 and Firefox ESR or Thunderbird before 102.11. Mozilla has not disclosed the triggering input, buffer operation, or code path beyond locating the invalid read in the RLBox Expat driver. Exploitation requires user interaction with attacker-controlled content and is limited to interrupting the affected application through a crash.

CVSS severity6.5
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in Mozilla's RLBox Expat driver allows attackers to crash Firefox before 113 and Firefox ESR or Thunderbird before 102.11. Mozilla has not disclosed the triggering input, buffer operation, or code path beyond locating the invalid read in the RLBox Expat driver. Exploitation requires user interaction with attacker-controlled content and is limited to interrupting the affected application through a crash.

The record

CVE
CVE-2023-32206
Published
Jun 2, 2023
Updated
May 27, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-125, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. May 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <113

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <113
Mozilla · Thunderbirdversion=unspecified <102.11
Mozilla · Firefox ESRversion=unspecified <102.11

Published CVSS scores

6.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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