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Threats / Apple / CVE-2023-41991
CVE-2023-41991 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Apple Multiple Products vulnerability

Apple iOS, iPadOS, macOS, and watchOS contain improper certificate validation allowing malicious apps to bypass signature verification.

Verdict

Today item — known-exploited.

A malicious application can exploit weak certificate validation to circumvent code signing protections across multiple Apple platforms. Active exploitation in the wild increases risk despite low EPSS score.

CISA KEV Yes · 2023-09-253EPSS 0.04547 (verify live)4Exploit Public PoC5
01

Is it exploitable?

— the evidence, ranked above the score
Exploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
15 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-09-25).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.04547 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Apple, Multiple Products. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-295 Improper Certificate Validation — weakness family: Authentication.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution not established

No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.

03

Why it matters

— the attack path, told twice: adversary, then board
1

Front door — unauthenticated access narrative 1

Attacker
I craft a malicious app that exploits improper certificate validation to forge or bypass Apple's code signature checks.
Business
Unauthorized code execution on user devices undermines platform security guarantees and erodes customer trust in app store protections.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I distribute the app through unofficial channels or social engineering, targeting users who may sideload or trust compromised sources.
Business
Increased support costs, reputational damage, and potential liability for data breaches resulting from compromised devices.
3

Lateral reach — past segmentation narrative 3

Attacker
I use the validation bypass to install persistent malware, steal credentials, or exfiltrate sensitive user data.
Business
Regulatory exposure under privacy laws, customer notification obligations, and potential class action litigation.
04

What to do

— defensible action
  • Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • Public PoC available (VulnCheck)
  • 15 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • Public exploit availability
  • Catalogued by apple (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by appleCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.