CVE-2026-22998: nvme-tcp: fix NULL pointer dereferences in nvmet_tcp_build_pdu_iovec
In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: fix NULL pointer dereferences in nvmettcpbuildpduiovec
Commit efa56305908b ("nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU length") added ttag bounds checking and dataoffset validation in nvmettcphandleh2cdatapdu(), but it did not validate whether the command's data structures (cmd->req.sg and cmd->iov) have been properly initialized before processing H2CDATA PDUs.
The nvmettcpbuildpduiovec() function dereferences these pointers without NULL checks. This can be triggered by sending H2CDATA PDU immediately after the ICREQ/ICRESP handshake, before sending a CONNECT command or NVMe write command.
Attack vectors that trigger NULL pointer dereferences: 1. H2CDATA PDU sent before CONNECT → both pointers NULL 2. H2CDATA PDU for READ command → cmd->req.sg allocated, cmd->iov NULL 3. H2CDATA PDU for uninitialized command slot → both pointers NULL
The fix validates both cmd->req.sg and cmd->iov before calling nvmettcpbuildpduiovec(). Both checks are required because: - Uninitialized commands: both NULL - READ commands: cmd->req.sg allocated, cmd->iov NULL - WRITE commands: both allocated
Other sources
In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: fix NULL pointer dereferences in nvmettcpbuildpduiovec
Commit efa56305908b ("nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU length") added ttag bounds checking and dataoffset validation in nvmettcphandleh2cdatapdu(), but it did not validate whether the command's data structures (cmd-req.sg and cmd-iov) have been properly initialized before processing H2CDATA PDUs.
The nvmettcpbuildpduiovec() function dereferences these pointers without NULL checks. This can be triggered by sending H2CDATA PDU immediately after the ICREQ/ICRESP handshake, before sending a CONNECT command or NVMe write command.
Attack vectors that trigger NULL pointer dereferences: 1. H2CDATA PDU sent before CONNECT → both pointers NULL 2. H2CDATA PDU for READ command → cmd-req.sg allocated, cmd-iov NULL 3. H2CDATA PDU for uninitialized command slot → both pointers NULL
The fix validates both cmd-req.sg and cmd-iov before calling nvmettcpbuildpduiovec(). Both checks are required because: - Uninitialized commands: both NULL - READ commands: cmd-req.sg allocated, cmd-iov NULL - WRITE commands: both allocated
— IBM
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
nvme-tcpto a version that resolves this vulnerability.Patch efa56305908b
Event History
Frequently Asked Questions
What is the severity of CVE-2026-22998?
The severity of CVE-2026-22998 is currently classified as medium due to its potential for causing system instability.
How do I fix CVE-2026-22998?
To fix CVE-2026-22998, you should update your Linux kernel to the patched version that includes the mitigation for the vulnerability.
What systems are affected by CVE-2026-22998?
CVE-2026-22998 affects the Linux kernel specifically in the nvme-tcp subsystem.
What does CVE-2026-22998 exploit?
CVE-2026-22998 exploits a NULL pointer dereference vulnerability that can lead to kernel panics.
Is there a workaround for CVE-2026-22998?
There are no recommended workarounds for CVE-2026-22998; the best practice is to apply the necessary kernel updates.