How severe is CVE-2018-9840?

CVE-2018-9840 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-9840 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-9840?

CVE-2018-9840 affects Signal. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-9840?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-9840 published?

CVE-2018-9840 was published on 2018-04-10 and last updated on 2026-06-17.

CVE-2018-9840

CVE-2018-9840 is a medium-severity vulnerability in Signal with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 4.6
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Signal
Published: 2018-04-10
Last modified: 2026-06-17

Description

The Open Whisper Signal app before 2.23.2 for iOS allows physically proximate attackers to bypass the screen locker feature via certain rapid sequences of actions that include app opening, clicking on cancel, and using the home button.

Frequently asked questions

What is CVE-2018-9840?: The Open Whisper Signal app before 2.23.2 for iOS allows physically proximate attackers to bypass the screen locker feature via certain rapid sequences of actions that include app opening, clicking on cancel, and using the home button.
How severe is CVE-2018-9840?: CVE-2018-9840 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-9840 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-9840?: CVE-2018-9840 affects Signal. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-9840?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-9840 published?: CVE-2018-9840 was published on 2018-04-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:signal:signal:*:*:*:*:*:iphone_os:*:*

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