What’s Vulnerable › Vulnerabilities

CVE-2023-5732: Address bar spoofing via bidirectional characters

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-10-25 · updated 2026-06-17

Description

An attacker could have created a malicious link using bidirectional characters to spoof the location in the address bar when visited. This vulnerability affects Firefox < 117, Firefox ESR < 115.4, and Thunderbird < 115.4.1.

Affected products

• Debian Linux: 10.0, 11.0
• Mozilla Firefox: before 117.0 — fixed in 117.0
• Mozilla Firefox ESR: before 115.4.1 — fixed in 115.4.1
• Mozilla Thunderbird: before 115.4.1 — fixed in 115.4.1

How to fix

Upgrade to a fixed version: Mozilla Firefox 117.0; Mozilla Firefox ESR 115.4.1; Mozilla Thunderbird 115.4.1. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1690979
• https://bugzilla.mozilla.org/show_bug.cgi?id=1836962
• https://lists.debian.org/debian-lts-announce/2023/10/msg00037.html
• https://lists.debian.org/debian-lts-announce/2023/10/msg00042.html
• https://www.debian.org/security/2023/dsa-5535
• https://www.debian.org/security/2023/dsa-5538
• https://www.mozilla.org/security/advisories/mfsa2023-34/
• https://www.mozilla.org/security/advisories/mfsa2023-46/
• https://www.mozilla.org/security/advisories/mfsa2023-47/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1690979
• https://bugzilla.mozilla.org/show_bug.cgi?id=1836962
• https://lists.debian.org/debian-lts-announce/2023/10/msg00037.html

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