Arm Trusted Firmware Out-of-Bounds Write Vulnerability
Arm · Trusted Firmware
The flaw is an out-of-bounds write in Arm Trusted Firmware M (through version 1.2), affecting its handling of calls from the Non-Secure world into secure functions while the Non-Secure processing environment runs in handler mode. An attacker who can run code in the Non-Secure world with local access and low privileges can trigger a system halt, overwrite secure data, or cause secure data to be printed, with no user interaction required.
In Arm Trusted Firmware M through 1.2, the NS world may trigger a system halt, an overwrite of secure data, or the printing out of secure data when calling secure functions under the NSPE handler mode.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 2/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 2 months before it was disclosed.
- First seen exploitedVulnCheck KEV evidence2 mo before
- Disclosedday 0
- Added to CISA KEVEU database agrees+5 mo
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
2 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order, 2 cited passages 2Privilege EscalationTA0004
Non-secure world escalates into secure world privileges
the NS world may trigger a system halt, an overwrite of secure data
ImpactTA0040
Triggered system halt causes application or system DoS
may trigger a system halt
Detection
0 rules for this CVE · 34 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2021-27562 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Exploitation for Privilege EscalationT106831 general rules
- Exploiting CVE-2019-1388criticalstable
- Audit CVE Eventcriticaltest
- HackTool - SysmonEOP Executioncriticaltest
- InstallerFileTakeOver LPE CVE-2021-41379 File Create Eventcriticaltest
- Possible Coin Miner CPU Priority Paramcriticaltest
- Potential CVE-2021-41379 Exploitation Attemptcriticaltest
- Potential SystemNightmare Exploitation Attemptcriticaltest
- Sudo Privilege Escalation CVE-2019-14287 - Builtincriticaltest
Application or System ExploitationT1499.0043 general rules
- Audit CVE Eventcriticaltest
- Apache Segmentation Faulthightest
- Nginx Core Dumphightest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX