Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
PR:H confirmed by 'authenticated and authorized operator' requirement; A:L reflects temporary reader restart with no data impact.
Primary rating from Vendor (Gallagher).
CVSS VectorVendor: Gallagher
Lifecycle Timeline
1DescriptionCVE.org
Uncaught Exception (CWE-248) in the T20 Readers allows an authenticated and authorized operator to trigger a restart by sending specific requests, resulting in a temporary denial of service. Version of Command Centre affected:
- 9.50 prior to vCR9.50.260616a (distributed in 9.50.1587(MR1))
- 9.40 prior to vCR9.40.260616a (distributed in 9.40.3130(MR3))
- 9.30 prior to vCR9.30.260616a (distributed in 9.30.3983(MR5))
- 9.20 prior to vCR9.20.260616a (distributed in 9.20.4349(MR7))
- all versions of 9.10 and prior.
AnalysisAI
Gallagher Command Centre's T20 Readers component crashes and restarts when an authenticated, high-privilege operator sends specific crafted requests, causing a temporary denial of service. Exploitation requires existing operator-level credentials and authorization - this cannot be triggered by unauthenticated or low-privilege users. The vulnerability carries a CVSS 2.7 (Low) score with no public exploit code and no CISA KEV listing, indicating minimal real-world threat beyond insider misuse or compromised operator accounts.
Technical ContextAI
The root cause is CWE-248 (Uncaught Exception): the T20 Reader process fails to handle a specific exception condition gracefully, resulting in a process restart rather than a controlled error response. T20 Readers are physical access control reader devices managed through Gallagher's Command Centre software platform. The affected CPE is cpe:2.3:a:gallagher:t-20_readers:*:*:*:*:*:*:*:*, indicating the vulnerability exists across all T20 Reader versions when paired with the affected Command Centre releases (9.10 through 9.50). The CVSS vector AV:N confirms the triggering request traverses the network, consistent with the operator-to-reader communication model in the Gallagher access control architecture.
RemediationAI
Vendor-released patches are available for supported branches: upgrade Command Centre to 9.50.1587 (MR1), 9.40.3130 (MR3), 9.30.3983 (MR5), or 9.20.4349 (MR7) as appropriate for your deployment, containing build vCR9.x0.260616a for the respective branch. Organizations on version 9.10 or earlier should treat this as an additional driver to upgrade to a supported release, as no fix will be backported to end-of-support branches. As a compensating control prior to patching, restrict the operator accounts permitted to interact with T20 Reader configuration to the minimum necessary personnel - this limits the pool of principals capable of triggering the condition, though it cannot eliminate the risk entirely. Full advisory and patch download details are at https://security.gallagher.com/en-NZ/Security-Advisories/CVE-2026-27790.
Same weakness CWE-248 – Uncaught Exception
View allSame technique Denial Of Service
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-42001
GHSA-56pq-38g7-f784