CVE-2023-29548Public exploitNetwork attack vector

Incorrect WebAssembly results via signed divisor lowering

Published Jun 2, 2023 · Updated Jan 10, 2025

Incorrect optimization in Mozilla Firefox and Thunderbird on ARM64 allows remote attackers to alter WebAssembly division results through crafted content. In src/jit/arm64/Lowering-arm64.cpp, lowerUDiv treats a constant unsigned divisor as signed, takes its absolute value, and lowers negative powers of two to identity or right-shift operations. Affected releases are Firefox and Android variants before 112 and Firefox ESR and Thunderbird before 102.10; execution requires ARM64 and user interaction, with only incorrect computation demonstrated.

CVSS severity6.5
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect optimization in Mozilla Firefox and Thunderbird on ARM64 allows remote attackers to alter WebAssembly division results through crafted content. In src/jit/arm64/Lowering-arm64.cpp, lowerUDiv treats a constant unsigned divisor as signed, takes its absolute value, and lowers negative powers of two to identity or right-shift operations. Affected releases are Firefox and Android variants before 112 and Firefox ESR and Thunderbird before 102.10; execution requires ARM64 and user interaction, with only incorrect computation demonstrated.

The record

CVE
CVE-2023-29548
Published
Jun 2, 2023
Updated
Jan 10, 2025
Vendor
Mozilla
Product
Firefox
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 10, 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 <112

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <112
Mozilla · Thunderbirdversion=unspecified <102.10
Mozilla · Firefox for Androidversion=unspecified <112
Mozilla · Firefox Focus for Androidversion=unspecified <112
Mozilla · Firefox ESRversion=unspecified <102.10

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

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.

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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 exploitPublished

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

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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