CVE Intelligence
Low Cryptography

CVE-2023-34414 — The error page for sites with invalid TLS certificates was missing the activation-delay Firefox...

The error page for sites with invalid TLS certificates was missing the activation-delay Firefox uses to protect prompts and permission dialogs from attacks that exploit human response time delays. If a malicious page elicited user clicks in precise locations immediately before navigating to a site with a certificate error and made the renderer extremely busy at the same time, it could create a gap between when the error page was loaded and when the display actually refreshed. With the right timing the elicited clicks could land in that gap and activate the button that overrides the certificate error for that site. This vulnerability affects Firefox ESR < 102.12, Firefox < 114, and Thunderbird < 102.12.

Published Jun 19, 2023 · Updated Oct 24, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: mozilla

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.9% (30-day exploitation probability)+9

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.9%
ahead of 59% of scored CVEs · Oct 25, 2026
Affects
Mozilla
Firefox and 2 more
CVSS base
3.1
Low · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. Search available logs for exploit probes matching the vulnerability class (cryptography), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Mozilla Firefox < 114.0 Vulnerable NIST National Vulnerability Database
Mozilla Firefox < 114 Vulnerable CVE Program (cve.org) e CISA ADP
Mozilla Firefox ESR < 102.12 Vulnerable NIST National Vulnerability Database
Mozilla Firefox ESR < 102.12 Vulnerable CVE Program (cve.org) e CISA ADP
Mozilla Thunderbird < 102.12 Vulnerable NIST National Vulnerability Database
Mozilla Thunderbird < 102.12 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
3.1 CVSS 3.1 Low 1.6 1.4 nvd@nist.gov via NIST National Vulnerability Database
3.1 CVSS 3.1 Low — — GitHub, Inc. via GitHub Security Advisories
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-295 · Improper Certificate Validation

Other CVEs with this weakness →

EPSS over time FIRST

Oct 23, 2026 → Oct 25, 2026 · 3 reading(s) · max 0.90%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Check TLS negotiations and unexpected certificates in the component’s traffic.
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · mozilla/firefox esr, mozilla/firefox, mozilla/thunderbird
    Oct 24, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 24, 2026
  • Affected products added · mozilla/firefox, mozilla/firefox esr, mozilla/thunderbird
    Oct 24, 2026 · NIST National Vulnerability Database
  • CVSS changed · 3.1
    Oct 24, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 24, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 24, 2026 · Alertas do Telegram
  • 2023
  • CVE published
    Jun 19, 2023 · mozilla

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 24, 2026 – Oct 24, 2026
  • 1× Official description updated · Oct 24, 2026 – Oct 24, 2026

References

8 on the record

Elsewhere on this site

Mozilla
every CVE for this vendor
Cryptography
same class
CWE-295
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-106016 Mitigation bypass in the File Handling component 19d
  • CVE-2026-103500 Heap buffer overflow opening large email 25d
  • CVE-2026-96869 Information disclosure in the Networking component 26d
  • CVE-2026-100828 Mitigation bypass in the Bookmarks & History component 26d
  • CVE-2026-100832 Use-after-free in the Graphics: Canvas2D component 26d
  • CVE-2026-100829 Mitigation bypass in the DOM: Security component 26d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-34414 is "The error page for sites with invalid TLS certificates was missing the activation-delay Firefox...", rated Low. It affects Firefox (Mozilla); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.1 describes technical severity. EPSS 0.90% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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