CVE-2023-5758Public exploitNetwork attack vector

Reflected XSS via unsafe reader-mode redirect

Published Oct 24, 2023 · Updated Jun 12, 2025

Reflected XSS in Mozilla Firefox for iOS before 119 allows remote attackers to execute script through a crafted reader-mode redirect URL. The localhost reader endpoint accepts a URL query parameter without rejecting its javascript scheme, then loads it when reader mode is toggled. A user must open the crafted reader URL and activate reader mode, after which the script can read or alter content in the localhost reader origin.

CVSS severity6.1
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Mozilla Firefox for iOS before 119 allows remote attackers to execute script through a crafted reader-mode redirect URL. The localhost reader endpoint accepts a URL query parameter without rejecting its javascript scheme, then loads it when reader mode is toggled. A user must open the crafted reader URL and activate reader mode, after which the script can read or alter content in the localhost reader origin.

The record

CVE
CVE-2023-5758
Published
Oct 24, 2023
Updated
Jun 12, 2025
Vendor
Mozilla
Product
Firefox for iOS
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Jun 12, 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 <119

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefox for iOSversion=unspecified <119

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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