Privilege escalation via unauthorized certificate override injection
Published Jul 21, 2026 · Updated Jul 21, 2026
Privilege escalation in Mozilla Firefox and Thunderbird before 153 allows attackers to persist arbitrary TLS certificate overrides. ContentParent::RecvAddCertException accepts attacker-controlled certificate, hostname, port, and persistence values from a compromised content process without authorization, then stores the override in the profile. A separate content-process compromise is required; the override survives restarts and suppresses future TLS warnings for a targeted non-HSTS-preloaded host during a matching man-in-the-middle attack.
Summary
What happened
Privilege escalation in Mozilla Firefox and Thunderbird before 153 allows attackers to persist arbitrary TLS certificate overrides. ContentParent::RecvAddCertException accepts attacker-controlled certificate, hostname, port, and persistence values from a compromised content process without authorization, then stores the override in the profile. A separate content-process compromise is required; the override survives restarts and suppresses future TLS warnings for a targeted non-HSTS-preloaded host during a matching man-in-the-middle attack.
The record
- CVE
- CVE-2026-16372
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-269, T1553
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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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.
Public exploit references
- Bugzilla certificate-override reproduction bundleproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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