CVE-2026-74557 scsi: libiscsi: Fix stale-data leak into the SCSI sense buffer
A malicious iSCSI target can leak stale kernel memory into the SCSI sense buffer, exposing sensitive data to userspace.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74557?
CVE-2026-74557 is a high-severity vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
scsi: libiscsi: Fix stale-data leak into the SCSI sense buffer
iscsi_scsi_cmd_rsp() copies the sense data of a SCSI Response from the target-supplied data segment. The segment carries a 2-byte sense length followed by the sense bytes, so it must hold 2 + senselen bytes, but the bounds check only requires datalen >= senselen:
senselen = get_unaligned_be16(data); if (datalen < senselen) goto invalid_datalen; memcpy(sc->sense_buffer, data + 2, min_t(uint16_t, senselen, SCSI_SENSE_BUFFERSIZE));
A target that returns a SCSI Response whose datalen equals senselen (with senselen <= SCSI_SENSE_BUFFERSIZE) makes the memcpy() from data + 2 read up to two bytes past the received data. Those bytes are stale conn->data contents and end up in the command's sense buffer, which is returned to userspace.
Account for the 2-byte sense length prefix in the check.
Which versions are affected by CVE-2026-74557?
How do I fix CVE-2026-74557?
Apply the vendor's patch.
Is CVE-2026-74557 being exploited?
There is no known exploitation of CVE-2026-74557 in the wild and no public exploit code.
Sources
Also known as AZL-96333, BELL-CVE-2026-74557, DEBIAN-CVE-2026-74557, GHSA-x575-q9wv-7p43, UBUNTU-CVE-2026-74557.