RDMA/rxe: insert mcg into mcg_tree only after rxe_mcast_add() succeeds
Noroxi assessment
Priority: Monitor (action score 28/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
- Fixed version: Linux Linux 02c0a2fa69c16248a7432af8a6d64ab2a73a5283, 1caceeb2d74bbe88223aea55eb8626b4c5f076fd, c79a789aa15180a1543b5db49c343d12e3ec214d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.
Low priority for now. Upgrade to Linux Linux 02c0a2fa69c16248a7432af8a6d64ab2a73a5283, 1caceeb2d74bbe88223aea55eb8626b4c5f076fd, c79a789aa15180a1543b5db49c343d12e3ec214d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: insert mcg into mcg_tree only after rxe_mcast_add() succeeds rxe_get_mcg() publishes a newly allocated multicast group in rxe->mcg_tree before programming the backing Ethernet multicast address with rxe_mcast_add(), which runs outside mcg_lock. A local userspace RDMA client reaches this path with ATTACH_MCAST on a UD QP; if rxe_mcast_add() then returns an error (for example -ENODEV when the backing netdev has been removed, or a propagated dev_mc_add() error), the unwind frees the published group without removing it from the tree. A later lookup of the same MGID dereferences the freed struct rxe_mcg from __rxe_lookup_mcg(). Fix this by keeping the new mcg private until rxe_mcast_add() succeeds. Split the tree publication into __rxe_publish_mcg(), call rxe_mcast_add() before taking the tree reference, and free the still-private mcg on failure. Because the group is never visible in mcg_tree until the multicast address is programmed, no concurrent caller can look it up or attach a QP to a group that is about to be torn down, so the error path needs no conditional unwind. If another caller publishes the same MGID while the address is being programmed, the post-add re-check under mcg_lock finds the winner; this caller then drops its private object and balances its own rxe_mcast_add() with rxe_mcast_del() before returning the winner. Reproduced by forcing the rxe_mcast_add() error return under KASAN: without the change the next attach to the same MGID reports a slab-use-after-free in __rxe_lookup_mcg(); with it the forced failure returns cleanly. A no-injection attach/detach regression, including a two-QP shared join/leave and re-attach, stays KASAN- and leak-clean.
- Published
- Oct 6, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.1% · 2th percentile
- CWE
- —
Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.0
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 5.18affected
- a926a903b7dc39a8a949150258c09290998dd812 and later · before ddb43ac0926d4a931bc9b7744b93627f627457e5affected · git
- a926a903b7dc39a8a949150258c09290998dd812 and later · before c79a789aa15180a1543b5db49c343d12e3ec214daffected · git
- a926a903b7dc39a8a949150258c09290998dd812 and later · before faae1fb4ccf8205806a8802c008798dabeb0205baffected · git
- a926a903b7dc39a8a949150258c09290998dd812 and later · before 02c0a2fa69c16248a7432af8a6d64ab2a73a5283affected · git
- a926a903b7dc39a8a949150258c09290998dd812 and later · before d4fc4e37f8a143b0fe83b42c8fb48cf542154feeaffected · git
- a926a903b7dc39a8a949150258c09290998dd812 and later · before 1caceeb2d74bbe88223aea55eb8626b4c5f076fdaffected · git
- before 5.18not affected · semver
- 6.1.189 and later · up to and including 6.1.*not affected · semver
- 6.6.158 and later · up to and including 6.6.*not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 6.1.190-1 | 6.1.190-1 |
| Debian:12 | linux-6.12 | before 6.12.113-1~deb12u1 | 6.12.113-1~deb12u1 |
| Debian:13 | linux | before 6.12.113-1 | 6.12.113-1 |
| Debian:14 | linux | before 7.2.8-1 | 7.2.8-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation40Plan
- CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment40Plan
- CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-98358Oct 6, 2026 · IB/iser: reject a remote invalidation of an unregistered direction0Monitor
- ← EarlierCVE-2026-98359Oct 6, 2026 · RDMA/core: Reject unregistering netdevs in ib_get_eth_speed28Monitor
- Later →CVE-2026-98361Oct 6, 2026 · RDMA/rxe: Restore HMM_PFN_WRITE check in ODP write paths31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 02c0a2fa69c16248a7432af8a6d64ab2a73a5283 | Vendor (CNA) |
| Linux Linux | 1caceeb2d74bbe88223aea55eb8626b4c5f076fd | Vendor (CNA) |
| Linux Linux | c79a789aa15180a1543b5db49c343d12e3ec214d | Vendor (CNA) |
| Linux Linux | d4fc4e37f8a143b0fe83b42c8fb48cf542154fee | Vendor (CNA) |
| Linux Linux | ddb43ac0926d4a931bc9b7744b93627f627457e5 | Vendor (CNA) |
| Linux Linux | faae1fb4ccf8205806a8802c008798dabeb0205b | Vendor (CNA) |
| azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 | 6.6.158.1-1 · Release Notes | Microsoft (MSRC) |
| debian:linux | 6.1.190-1 · Debian:12 | Package registry (OSV) |
| debian:linux | 6.12.113-1 · Debian:13 | Package registry (OSV) |
| debian:linux | 7.2.8-1 · Debian:14 | Package registry (OSV) |
| debian:linux-6.12 | 6.12.113-1~deb12u1 · Debian:12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recordedsame day
- TodayOct 25, 2026+19 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- CVSS— → 7
- Severity— → high
- Exploit maturity— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (5 more)Show less
- git.kernel.org/stable/c/1caceeb2d74bbe88223aea55eb8626b4c5f076fd
- git.kernel.org/stable/c/c79a789aa15180a1543b5db49c343d12e3ec214d
- git.kernel.org/stable/c/d4fc4e37f8a143b0fe83b42c8fb48cf542154fee
- git.kernel.org/stable/c/ddb43ac0926d4a931bc9b7744b93627f627457e5
- git.kernel.org/stable/c/faae1fb4ccf8205806a8802c008798dabeb0205b
Vendor advisories and official records. Exploit/PoC links are deliberately left out.