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CVE-2026-100075
RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters
Published 2026-09-25 (24 days ago) by the Linux kernel CNA. Subsystem drivers/infiniband. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-100075 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
When srpt_alloc_rw_ctxs() fails partway through a multi-buffer indirect descriptor, the unwind path destroys RDMA contexts but leaves stale n_rw_ctx and n_rdma values (and a dangling rw_ctxs pointer). Later sq_wr_avail accounting in srpt_queue_response() or srpt_write_pending() can then subtract the wrong number of send queue credits. Reset the counters and clear rw_ctxs after freeing the heap allocation before returning an error.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/infiniband/ulp/srpt/ib_srpt.c
- What this is
- SCSI RDMA PROTOCOL (SRP) TARGETMAINTAINERS section matched on drivers/infiniband/ulp/srpt/ · linux-rdma@vger.kernel.org · Supported
- Kernel module
- ib_srpt
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_INFINIBAND_SRPT' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w ib_srptPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookworm, trixie, forky, sid, bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_INFINIBAND, CONFIG_INFINIBAND_SRPT
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-09-25 (24 days ago)source
- CVSS
- 9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.42%, higher than 35.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/infiniband
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.7 | 5.10.270 | af00051dbc9f |
| 4.7 | 5.15.221 | 717ab4d0614e |
| 4.7 | 6.1.188 | f1f2252da52c |
| 4.7 | 6.6.157 | f65f45dfa1e6 |
| 4.7 | 6.12.110 | be1478849e1a |
| 4.7 | 6.18.52 | af073bd24518 |
| 4.7 | 7.2.6 | bd02d644bd19 |
| 4.7 | 7.3 | b38f98e17605 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:NAttack vector, network
- The descriptor table that makes srpt_alloc_rw_ctxs() fail partway (idb->desc_list entries, table_desc.len, data_out/in_desc_cnt) comes in a remote initiator's SRP_CMD IU. The path is srpt_recv_done->srpt_handle_new_iu->srpt_handle_cmd->srpt_get_desc_tbl, and srpt also accepts logins through its RDMA-CM listener, which runs over routable RoCEv2 (UDP/IP).
- AC:LAttack complexity, low
- The initiator picks the failure point: a small first descriptor followed by one with db->len=0xFFFFFFFF, whose scatterlist array is too big for sgl_alloc_order() to allocate. target_alloc_sgl() then fails at i>=1 every time, leaving n_rw_ctx>=1 and a dangling rw_ctxs. No race or outside state is needed.
- PR:NPrivileges required, none
- SRP login (srpt_cm_req_recv) has no authentication. It only compares the initiator port ID that the initiator itself claims against the configured ACL, and the malformed SRP_CMD is parsed right after login.
- UI:NUser interaction, none
- The initiator sends the malformed SRP_CMD over its own channel, and no action by the target's administrator or any user is needed.
- S:UScope, unchanged
- The use-after-free and crash happen in the target host's kernel, which is the same security authority that runs ib_srpt. No VM or IOMMU boundary is crossed.
- C:HConfidentiality impact, high
- In kernels from v4.7 up to v5.1, srpt_handle_cmd's release_ioctx path calls srpt_release_cmd(). Because n_rw_ctx is stale, srpt_free_rw_ctxs() reads the kfree'd rw_ctxs array, a use-after-free on a slab object the attacker can reclaim.
- I:HIntegrity impact, high
- The same srpt_free_rw_ctxs() pass calls rdma_rw_ctx_destroy() and target_free_sgl() again on ctx->sg lists the unwind loop already freed. That is a double free of the scatterlists and their data pages, a memory-corruption primitive.
- A:HAvailability impact, high
- Each malformed SRP_CMD can be repeated at will and corrupts the heap (UAF plus double free) on older kernels. On newer kernels the busy path reached after this failure crashes the target, so any initiator can repeatedly take down the SRP target host.