svcrdma: Validate Read chunk positions before reconstruction
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 16 fixed, 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: svcrdma: Validate Read chunk positions before reconstruction The RPC/RDMA Read chunk position field is supplied by the remote client and stored verbatim in the parsed chunk list. xdr_count_read_segments() checks only 4-byte alignment; it never compares the position against the received inline body length. In the single-chunk path, svc_rdma_read_complete_one() splits the head and tail kvecs at ch_position. A position past the inline body underflows the tail length, exposing adjacent slab memory to the upper XDR decoder. In the multi-chunk path, svc_rdma_read_multiple_chunks() computes gap lengths between chunks as unsigned subtractions from ch_position. Overlapping Read chunks cause these subtractions to underflow. A final position past the inline body likewise underflows the trailing gap length. svc_rdma_copy_inline_range() then copies past the receive buffer into request pages that are returned to the client through the Reply channel. Bound inline-range copies in svc_rdma_copy_inline_range() against the decoded inline RPC body saved in rc_saved_arg. Reject a single Read chunk positioned beyond that body, and reject multi-chunk lists where accumulated read bytes exceed the next chunk's position. Apply the same position and overlap checks in the call-chunk interleaving path.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.109, 6.18.50, 7.2.4, 7.3
Red Hat 4 advisories
- RHSA-2026:83207 Released 2026-10-15 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- 10Base-SMTV kernel-modules-internal-6.12.0-211.66.1.el10_2
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.66.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.66.1.el10_2, kernel-64k-devel-6.12.0-211.66.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.66.1.el10_2, kernel-64k-6.12.0-211.66.1.el10_2, kernel-64k-core-6.12.0-211.66.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.66.1.el10_2, libperf-6.12.0-211.66.1.el10_2
- Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.66.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.66.1.el10_2, kernel-rt-64k-6.12.0-211.66.1.el10_2, kernel-rt-64k-core-6.12.0-211.66.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.66.1.el10_2, kernel-rt-core-6.12.0-211.66.1.el10_2, kernel-rt-debug-6.12.0-211.66.1.el10_2 +9
- RHSA-2026:83156 Released 2026-10-14 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.58.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.58.1.el9_8, kernel-64k-devel-5.14.0-687.58.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.58.1.el9_8, kernel-64k-5.14.0-687.58.1.el9_8, kernel-64k-core-5.14.0-687.58.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.58.1.el9_8, libperf-5.14.0-687.58.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.58.1.el9_8, kernel-rt-64k-5.14.0-687.58.1.el9_8, kernel-rt-64k-core-5.14.0-687.58.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.58.1.el9_8, kernel-rt-core-5.14.0-687.58.1.el9_8, kernel-rt-debug-5.14.0-687.58.1.el9_8 +9
- RHSA-2026:83157 Released 2026-10-14 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.174.1.el8_10, kernel-4.18.0-553.174.1.el8_10, kernel-abi-stablelists-4.18.0-553.174.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.174.1.el8_10
Show 1 more Red Hat advisories
- RHSA-2026:83159 Released 2026-10-14 · Red Hat rating Importantkernel-rt security, bug fix, and enhancement update
- Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-core-4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-debug-4.18.0-553.174.1.rt7.515.el8_10 +9
- Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-core-4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-debug-4.18.0-553.174.1.rt7.515.el8_10 +7
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| 10Base-SMTV | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:83156 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:83157 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:83156 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:83157 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:83156 |
| Red Hat Enterprise Linux Hidden (v. 10) | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:83159 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:83159 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:83156 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:83207 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:83156 |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89526
- 2026-10-03 Alias added: GHSA-jj8v-vrfx-wp8w
- 2026-10-05 EPSS moved to the below the 50th percentile
- 2026-10-16 Fix available: RHSA-2026:83159 · Red Hat
- 2026-10-16 Fix available: RHSA-2026:83156 · Red Hat
- 2026-10-16 Fix available: RHSA-2026:83157 · Red Hat
- 2026-10-16 Fix available: RHSA-2026:83207 · Red Hat
- 2026-10-16 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux AppStream (v. 9) +13 · Red Hat
- 2026-10-18 CISA SSVC decision points changed
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@3861eeabaebe243050952b34063763527c44e1fe, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-25 EPSS moved to the 50th–90th percentile
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@6388f2ed36c10f59d926735b92c2b152d2c635e5 · CNA
- 2026-10-30 1 new reference · CNA
References
Other 6
- https://git.kernel.org/stable/c/6388f2ed36c10f59d926735b92c2b152d2c635e5
- https://git.kernel.org/stable/c/3861eeabaebe243050952b34063763527c44e1fe
- https://git.kernel.org/stable/c/5ab3f6d882fe07ae5e61d0bcfeea00b9409155c2
- https://git.kernel.org/stable/c/f84ec84d8d4bc65f9ae23372570349687f66fa39
- https://git.kernel.org/stable/c/577097455d084610fc31e91e6a61c5793b6f04ba
- https://git.kernel.org/stable/c/3779b7b9e7d1c8ba4738f9d327de3b0288cefe9b
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Sources
- CVE-2026-89526 · CVE Program
- CVE-2026-89526 · NVD
- FIRST EPSS
- GHSA-jj8v-vrfx-wp8w · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89526 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences