CVE-2026-90274 coresight: etm4x: fix underflow for usage of (nrseqstate - 1)
An integer underflow in the Linux kernel's CoreSight ETM4x driver can cause a denial of service when specific hardware configurations are present.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90274?
CVE-2026-90274 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
coresight: etm4x: fix underflow for usage of (nrseqstate - 1)
According to IHI006H Embedded Trace Macrocell Architecture Specification[0], TRCSEQEVR<n> is implemented only when TRCIDR5.NUMSEQSTATE is 0b100, in which case n ranges from 0 to 2; otherwise, TRCIDR5.NUMSEQSTATE is 0b000.
IOW, the number of usage in the initialisation or setting TRCSEQEVR<n> with drvdata->nrseqstate - 1 in the loop could make underflow issue when TRCIDR5.NUMSEQSTATE is 0b000.
Therefore, introduce nr_seq_ctrls field and untie it from nrseqstate. As part of this introduce ETM_MAX_SEQ_TRANSITIONS macro and apply nr_seq_ctrls and above macro to TRCSEQEVR<n> relevant fields setup.
Which versions are affected by CVE-2026-90274?
How do I fix CVE-2026-90274?
Apply the vendor's patch.
Is CVE-2026-90274 being exploited?
There is no known exploitation of CVE-2026-90274 in the wild and no public exploit code.
Sources
Also known as AZL-102915, BELL-CVE-2026-90274, DEBIAN-CVE-2026-90274, GHSA-2fmc-xx62-q6fm, UBUNTU-CVE-2026-90274.