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CVE-2026-80945
crypto: iaa - unmap dst before software fallback on decompress
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/crypto. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-80945 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| 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
On a hardware analytics error, decompress retries through the software fallback, which writes req->dst with the CPU while it is still mapped DMA_FROM_DEVICE. With SWIOTLB active the later dma_unmap_sg() copies the stale bounce buffer over req->dst, corrupting the result. Unmap before the fallback runs. The async path unmaps inline; the sync path signals the retry with -EAGAIN so iaa_comp_adecompress() runs the fallback after unmapping.
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/crypto/intel/iaa/iaa_crypto_main.c
- What this is
- INTEL IAA CRYPTO DRIVERMAINTAINERS section matched on drivers/crypto/intel/iaa/* · linux-crypto@vger.kernel.org · Supported
- Kernel module
- iaa_crypto
Check it on the machine
grep -wE 'CONFIG_CRYPTO|CONFIG_CRYPTO_DEV_IAA_CRYPTO' /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 iaa_cryptoPrints 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. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixieMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- ?
- not established - no Makefile entry for the affected file
- M
- a module where it is built at all; some flavours do not build it
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_CRYPTO, CONFIG_CRYPTO_DEV_IAA_CRYPTO
- 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
- 2026-09-11 (37 days ago)source
- CVSS
- 9.1 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Nsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.50%, higher than 41.5% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/crypto
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.8 | 6.12.111 | c0279e5ea2aa |
| 6.8 | 6.18.51 | fc933a4a419b |
| 6.8 | 7.2.4 | fcd86180ef78 |
| 6.8 | 7.3 | 94a259304771 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| 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
- iaa_crypto registers cra_name "deflate" at priority 300, so IPComp's crypto_alloc_acomp("deflate") selects deflate-iaa. Inbound packets reach iaa_comp_adecompress via xfrm_input → ipcomp_input → crypto_acomp_decompress, so a remote IPsec/IPComp peer can trigger the bug.
- AC:LAttack complexity, low
- The peer fully controls the compressed payload and can send non-IAA/invalid deflate that deterministically returns IAA_ANALYTICS_ERROR and takes the software fallback. SWIOTLB bounce, which makes dma_unmap_sg overwrite dest, is a normal IAA deployment (legacy/no-IOMMU or TDX), not an attacker-uncontrolled race.
- PR:NPrivileges required, none
- The IPComp receive path decompresses packets that match an installed SA with no local account or capability check. IAA workqueue and xfrm SA setup are deployment preconditions, not attacker privileges, matching other IPComp/IAA scores in this CNA.
- UI:NUser interaction, none
- No victim action is required; attacker-sent IPComp packets automatically run hardware decompress, the analytics-error fallback, and the later dma_unmap_sg copy-back.
- S:UScope, unchanged
- The stale bounce copy-back corrupts the request dest buffer inside this kernel (IPComp skb pages or zswap folios) and does not cross a VM, IOMMU, or other security-authority boundary.
- C:HConfidentiality impact, high
- On SWIOTLB unmap of a DMA_FROM_DEVICE dest, the bounce slot is copied over req->dst. Those slots retain leftover bytes from prior DMA (other zswap pages, packets, or devices), disclosing that data into the decompressed output at dest size (a page up to the IPComp scratch, tens of KB).
- I:HIntegrity impact, high
- Software fallback first writes the correct plaintext, then dma_unmap_sg silently replaces it with bounce contents. The kernel then treats that leftover DMA data as the decompressed result, injecting it into the post-auth IPComp inner-packet path or into zswap-restored pages.
- A:NAvailability impact, none
- The fallback returns success and the defect is silent dest corruption; it does not oops, panic, hang, deadlock, or leak allocations, so there is no availability impact beyond the integrity loss.