CVE-2026-64422: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes
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. No special conditions are required; it is repeatable.
- Fixed version: Linux Linux 27ddf4486c7dbf5bdd393fa8bef6b67179796d98, 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae, 99206ce2244f8a3ed64298d0667c9055845a5dc7; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1.
Low priority for now. Upgrade to Linux Linux 27ddf4486c7dbf5bdd393fa8bef6b67179796d98, 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae, 99206ce2244f8a3ed64298d0667c9055845a5dc7; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1 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: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid `net.ipv4.tcp_reordering` values before they reach TCP socket state. The sysctl is stored as an `int` but copied into the `u32` `tp->reordering` field for new sockets, so negative writes wrap to large values. With `tcp_mtu_probing=2`, the wrapped value can overflow the `tcp_mtu_probe()` size calculation and drive the MTU probing path into an out-of-bounds read. Route `tcp_reordering` writes through `proc_dointvec_minmax()` and require it to be at least 1. Also require `tcp_max_reordering` to be at least 1 so the configured maximum cannot become negative either. When registering the table for a non-init network namespace, relocate `extra2` pointers that refer into `init_net.ipv4` so the `tcp_reordering` upper bound follows that namespace's `tcp_max_reordering`. Harden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`. This keeps the send queue and window checks from being bypassed through signed integer overflow.
- Published
- Jul 25, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.1% · 3th percentile
- CWE
- CWE-190
Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.1
- 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.
Running WordPress? Scan your site free with WP Lens
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.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel2.6.24.1 and later · before 5.10.261
- linux linux kernel5.11 and later · before 5.15.212
- linux linux kernel5.16 and later · before 6.1.178
- linux linux kernel6.2 and later · before 6.6.145
- linux linux kernel6.7 and later · before 6.12.96
- linux linux kernel6.13 and later · before 6.18.39
- linux linux kernel6.19 and later · before 7.1.4
- linux linux kernel2.6.24
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
- 2.6.24affected
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before f0d88a4cd03affff6c08adf6c63964e235aede43affected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before 27ddf4486c7dbf5bdd393fa8bef6b67179796d98affected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efaeaffected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before e81f805824a8109504fce090641b17d135b48cd1affected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before 99206ce2244f8a3ed64298d0667c9055845a5dc7affected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before bbae351c0f32f7c200249e4aa6561b2b419dcf69affected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before a094ac95d3b69adfa1676eb9c8eae6835d4f1671affected · git
- 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf and later · before efb8763d7bbb40cff4cc55a6b62c3095a038149caffected · git
- before 2.6.24not 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 6.1.180-1 | 6.1.180-1 |
| Debian:12 | linux-6.12 | before 6.12.100-1~deb12u1 | 6.12.100-1~deb12u1 |
| Debian:13 | linux | before 6.12.96-1 | 6.12.96-1 |
| Debian:14 | linux | before 7.1.4-1 | 7.1.4-1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-64kb | before 5.14.21-150400.24.243.1 | 5.14.21-150400.24.243.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-docs | before 5.14.21-150400.24.243.1 | 5.14.21-150400.24.243.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-obs-build | before 5.14.21-150400.24.243.1 | 5.14.21-150400.24.243.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-syms | before 5.14.21-150400.24.243.1 | 5.14.21-150400.24.243.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-64kb | before 5.14.21-150500.55.192.2 | 5.14.21-150500.55.192.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-docs | before 5.14.21-150500.55.192.1 | 5.14.21-150500.55.192.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-obs-build | before 5.14.21-150500.55.192.2 | 5.14.21-150500.55.192.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-syms | before 5.14.21-150500.55.192.1 | 5.14.21-150500.55.192.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kernel-default | before 4.12.14-122.336.1 | 4.12.14-122.336.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_89 | before 1-8.3.1 | 1-8.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP4 | kernel-livepatch-SLE15-SP4_Update_60 | before 1-150400.9.3.1 | 1-150400.9.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_46 | before 1-150500.11.3.2 | 1-150500.11.3.2 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-default | before 6.4.0-150600.23.138.1 | 6.4.0-150600.23.138.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_32 | before 1-150600.13.3.1 | 1-150600.13.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_23 | before 1-150700.15.3.2 | 1-150700.15.3.2 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_22 | before 1-150700.1.3.1 | 1-150700.1.3.1 |
| SUSE:Linux Enterprise Micro 5.3 | kernel-default | before 5.14.21-150400.24.243.1 | 5.14.21-150400.24.243.1 |
| SUSE:Linux Enterprise Micro 5.3 | kernel-default-base | before 5.14.21-150400.24.243.1.150400.24.122.1 | 5.14.21-150400.24.243.1.150400.24.122.1 |
| SUSE:Linux Enterprise Micro 5.3 | kernel-rt | before 5.14.21-150400.15.189.1 | 5.14.21-150400.15.189.1 |
| SUSE:Linux Enterprise Micro 5.3 | kernel-source | before 5.14.21-150400.24.243.1 | 5.14.21-150400.24.243.1 |
+41
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
Published before and after this one in the same product
- ← EarlierCVE-2026-64413Jul 25, 2026 · netfilter: ebtables: zero chainstack array28Monitor
- ← EarlierCVE-2026-64420Jul 25, 2026 · mfd: cros_ec: Delay dev_set_drvdata() until probe success28Monitor
- Later →CVE-2026-64423Jul 25, 2026 · ipv4: igmp: remove multicast group from hash table on device destruction31Monitor
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 | 27ddf4486c7dbf5bdd393fa8bef6b67179796d98 | Vendor (CNA) |
| Linux Linux | 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae | Vendor (CNA) |
| Linux Linux | 99206ce2244f8a3ed64298d0667c9055845a5dc7 | Vendor (CNA) |
| Linux Linux | a094ac95d3b69adfa1676eb9c8eae6835d4f1671 | Vendor (CNA) |
| Linux Linux | bbae351c0f32f7c200249e4aa6561b2b419dcf69 | Vendor (CNA) |
| Linux Linux | e81f805824a8109504fce090641b17d135b48cd1 | Vendor (CNA) |
| Linux Linux | efb8763d7bbb40cff4cc55a6b62c3095a038149c | Vendor (CNA) |
| Linux Linux | f0d88a4cd03affff6c08adf6c63964e235aede43 | Vendor (CNA) |
| azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 | 6.6.145.2-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| debian:linux | 6.1.180-1 · Debian:12 | Package registry (OSV) |
| debian:linux-6.12 | 6.12.100-1~deb12u1 · Debian:12 | Package registry (OSV) |
| suse:kernel-64kb | 6.4.0-150600.23.138.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS | Package registry (OSV) |
| suse:kernel-default | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-default | 6.4.0-159998.54.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-default-base | 6.4.0-150600.23.138.1.150600.12.64.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS | Package registry (OSV) |
| suse:kernel-default-base | 6.4.0-159998.54.1.159998.21.40 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-docs | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-ec2 | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-kvmsmall | 6.4.0-159998.54.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP6_Update_32 | 1-150600.13.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6 | Package registry (OSV) |
| suse:kernel-obs-build | 6.4.0-150600.23.138.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS | Package registry (OSV) |
| suse:kernel-source | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-source | 6.4.0-159998.54.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
| suse:kernel-syms | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-trace | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-xen | 3.0.101-108.223.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | Package registry (OSV) |
| suse:kernel-zfcpdump | 6.4.0-150600.23.138.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS | 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.
No dated events beyond publication.
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.
- CVE-2026-4632546 days apartRDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE39Monitor
- CVE-2026-4603959 days apartrxgk: Fix potential integer overflow in length check39Monitor
- CVE-2026-4334178 days apartnet/ipv6: ioam6: prevent schema length wraparound in trace fill39Monitor
- CVE-2026-3163392 days apartrxrpc: Fix integer overflow in rxgk_verify_response()39Monitor
- CVE-2026-3164992 days apartnet: stmmac: fix integer underflow in chain mode39Monitor
- CVE-2026-3165992 days apartbatman-adv: reject oversized global TT response buffers39Monitor
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.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-190 · Integer Overflow or WraparoundCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (9 more)Show less
- git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae
- git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7
- git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671
- git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69
- git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1
- git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c
- git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.