UBUNTU-CVE-2026-46081
In the Linux kernel, the following vulnerability has been resolved: crypto: acomp - fix wrong pointer stored by acomp_save_req() acomp_save_req() stores &req->chain in req->base.data. When acomp_reqchain_done() is invoked on asynchronous completion, it receives &req->chain as the data argument but casts it directly to struct acomp_req. Since data points to the chain member, all subsequent field accesses are at a wrong offset, resulting in memory corruption. The issue occurs when an asynchronous hardware implementation, such as the QAT driver, completes a request that uses the DMA virtual address interface (e.g. acomp_request_set_src_dma()). This combination causes crypto_acomp_compress() to enter the acomp_do_req_chain() path, which sets acomp_reqchain_done() as the completion callback via acomp_save_req(). With KASAN enabled, this manifests as a general protection fault in acomp_reqchain_done(): general protection fault, probably for non-canonical address 0xe000040000000000 KASAN: probably user-memory-access in range [0x0000400000000000-0x0000400000000007] RIP: 0010:acomp_reqchain_done+0x15b/0x4e0 Call Trace: <IRQ> qat_comp_alg_callback+0x5d/0xa0 [intel_qat] adf_ring_response_handler+0x376/0x8b0 [intel_qat] adf_response_handler+0x60/0x170 [intel_qat] tasklet_action_common+0x223/0x820 handle_softirqs+0x1ab/0x640 </IRQ> Fix this by storing the request itself in req->base.data instead of &req->chain, so that acomp_reqchain_done() receives the correct pointer. Simplify acomp_restore_req() accordingly to access req->chain directly.
02 / AFFECTED SOFTWARE
Affected packages
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78 explicit affected versions
14 explicit affected versions
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03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: crypto: acomp - fix wrong pointer stored by acomp_save_req() acomp_save_req() stores &req->chain in req->base.data. When acomp_reqchain_done() is invoked on asynchronous completion, it receives &req->chain as the data argument but casts it directly to struct acomp_req. Since data points to the chain member, all subsequent field accesses are at a wrong offset, resulting in memory corruption. The issue occurs when an asynchronous hardware implementation, such as the QAT driver, completes a request that uses the DMA virtual address interface (e.g. acomp_request_set_src_dma()). This combination causes crypto_acomp_compress() to enter the acomp_do_req_chain() path, which sets acomp_reqchain_done() as the completion callback via acomp_save_req(). With KASAN enabled, this manifests as a general protection fault in acomp_reqchain_done(): general protection fault, probably for non-canonical address 0xe000040000000000 KASAN: probably user-memory-access in range [0x0000400000000000-0x0000400000000007] RIP: 0010:acomp_reqchain_done+0x15b/0x4e0 Call Trace: <IRQ> qat_comp_alg_callback+0x5d/0xa0 [intel_qat] adf_ring_response_handler+0x376/0x8b0 [intel_qat] adf_response_handler+0x60/0x170 [intel_qat] tasklet_action_common+0x223/0x820 handle_softirqs+0x1ab/0x640 </IRQ> Fix this by storing the request itself in req->base.data instead of &req->chain, so that acomp_reqchain_done() receives the correct pointer. Simplify acomp_restore_req() accordingly to access req->chain directly.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/d7e20b9bd6c990773cf0c09e2642250b8a70263d
- https://ubuntu.com/security/CVE-2026-46081
- https://ubuntu.com/security/notices/USN-8488-1
- https://ubuntu.com/security/notices/USN-8488-2
- https://ubuntu.com/security/notices/USN-8489-1
- https://ubuntu.com/security/notices/USN-8507-1
- https://ubuntu.com/security/notices/USN-8569-1
- https://ubuntu.com/security/notices/USN-8603-1
- https://www.cve.org/CVERecord?id=CVE-2026-46081