CVE-2022-49820: mctp i2c: don't count unused / invalid keys for flow release

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-01 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: mctp i2c: don't count unused / invalid keys for flow release We're currently hitting the WARN_ON in mctp_i2c_flow_release: if (midev->release_count > midev->i2c_lock_count) { WARN_ONCE(1, "release count overflow"); This may be hit if we expire a flow before sending the first packet it contains - as we will not be pairing the increment of release_count (performed on flow release) with the i2c lock operation (only performed on actual TX). To fix this, only release a flow if we've encountered it previously (ie, dev_flow_state does not indicate NEW), as we will mark the flow as ACTIVE at the same time as accounting for the i2c lock operation. We also need to add an INVALID flow state, to indicate when we've done the release.

Affected products

Linux kernel: from 5.18 before 6.0.10; 6.1-rc1, 6.1-rc2, 6.1-rc3, 6.1-rc4, 6.1-rc5 — fixed in 6.0.10

How to fix

Upgrade to a fixed version: Linux kernel 6.0.10. Check the vendor advisory for mitigations.

References

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