HOMEVULNERABILITIESCVE-2018-9840
MEDIUM

CVE-2018-9840

NVD-CWE-noinfoPublished: April 10, 2018· Updated: Jun 17, 2026

6.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2018-9840 requires local access, meaning attackers must already have a foothold on the target system.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 6.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorPhysical
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

signal1 product(s)
signal
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/signalapp/Signal-iOS/commit/018a35df7b42b4941cb4dfc9f462b37c3fafd9e9
PATCHhttps://github.com/signalapp/Signal-iOS/commits/release/2.23.2
PATCHhttps://github.com/signalapp/Signal-iOS/commit/018a35df7b42b4941cb4dfc9f462b37c3fafd9e9
PATCHhttps://github.com/signalapp/Signal-iOS/commits/release/2.23.2
ADVISORYhttp://nint.en.do/Signal-Bypass-Screen-locker.php
ADVISORYhttp://nint.en.do/Signal-Bypass-Screen-locker.php

All References (6)

→
http://nint.en.do/Signal-Bypass-Screen-locker.phpBroken Link · Third Party Advisory
→
https://github.com/signalapp/Signal-iOS/commit/018a35df7b42b4941cb4dfc9f462b37c3fafd9e9Patch · Third Party Advisory
→
https://github.com/signalapp/Signal-iOS/commits/release/2.23.2Issue Tracking · Patch · Third Party Advisory
→
http://nint.en.do/Signal-Bypass-Screen-locker.phpBroken Link · Third Party Advisory
→
https://github.com/signalapp/Signal-iOS/commit/018a35df7b42b4941cb4dfc9f462b37c3fafd9e9Patch · Third Party Advisory
→
https://github.com/signalapp/Signal-iOS/commits/release/2.23.2Issue Tracking · Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2018-9840
CVSS Score6.8 / 10
SeverityMEDIUM
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedApr 10, 2018

Related CVEs (NVD-CWE-noinfo)

CVE-2021-2317
10.0
CVE-2021-2256
10.0
CVE-2021-2244
10.0
CVE-2021-2177
10.0
CVE-2021-2248
10.0
CVE-2016-20010
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2018-9840 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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