Live › vulnerability › CVE-2026-98479
Go to dashboardThe Linux kernel iSCSI TCP initiator accepted a Data-In PDU for a command that was writing, so a malicious or compromised iSCSI target can inject its own bytes into the initiator's write buffers. The result is silent data corruption in O_DIRECT and page-cache writes, with the target's data read back from the cache.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Hosts running the Linux kernel's iSCSI TCP initiator (libiscsi_tcp) that connect to iSCSI targets and perform writes. The exposure depends on trusting the target, since the flaw needs a target that sends a Data-In for a write command. Hosts without iSCSI initiator use can skip it.
No product ranges from the sources yet.
uname -r and compare against the kernel version that includes the iscsi_tcp Data-In direction fix in the vendor's advisorylsmod | grep libiscsi_tcpiscsiadm -m sessionEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
scsi: libiscsi_tcp: Check the data direction of a Data-In PDU
The Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task and copies the PDU's data segment into that command's scatterlist without asking whether the command was reading. iscsi_tcp_r2t_rsp() in the same file does ask, and rejects an R2T for a command that is not DMA_TO_DEVICE.
A target that answers a WRITE command's ITT with a Data-In therefore has the initiator write target-supplied bytes into the pages that write was about to send. Those are the caller's own pinned pages for an O_DIRECT write, and page cache pages for a buffered one.
Observed against a test target that emits one 512-byte Data-In naming a 128 KB write's ITT, after the R2T for that write. With O_DIRECT the caller's buffer ends up holding 512 bytes of the target's data while pwrite() returns 131072. Buffered is quieter: pwrite() and fsync() both succeed, nothing is logged, and reading those blocks back returns the target's bytes out of the page cache without a command going on the wire.
Check the direction before using the scatterlist, the way the R2T path already does.
This page as .md · .json · in your agent: get_signal("CVE-2026-98479")
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