CVE-2025-39718: vsock/virtio: Validate length in packet header before skb_put()
Noroxi assessment
Priority: Monitor (action score 22/100)
- 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: 0.16% (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 0dab92484474587b82e8e0455839eaf5ac7bf894, 6.1.149, 676f03760ca1d69c2470cef36c44dc152494b47c; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1.
- Severity is disputed: the assigning authority (CNA) scores it 8.4, NVD 5.5.
Low priority for now. Upgrade to Linux Linux 0dab92484474587b82e8e0455839eaf5ac7bf894, 6.1.149, 676f03760ca1d69c2470cef36c44dc152494b47c; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1 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: vsock/virtio: Validate length in packet header before skb_put() When receiving a vsock packet in the guest, only the virtqueue buffer size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately, virtio_vsock_skb_rx_put() uses the length from the packet header as the length argument to skb_put(), potentially resulting in SKB overflow if the host has gone wonky. Validate the length as advertised by the packet header before calling virtio_vsock_skb_rx_put().
- Published
- Sep 5, 2025
- Updated
- Oct 19, 2026
- EPSS
- 0.1% · 5th percentile
- CWE
- CWE-787
Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 5.5
- CNA · Linux
- 8.4
- 2.9 point gap
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux11.0
- linux linux kernel6.1.63 and later · before 6.1.149
- linux linux kernel6.3 and later · before 6.6.103
- linux linux kernel6.7 and later · before 6.12.44
- linux linux kernel6.13 and later · before 6.16.4
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
- 6.3affected
- baddcc2c71572968cdaeee1c4ab3dc0ad90fa765 and later · before 969b06bd8b7560efb100a34227619e7d318fbe05affected · git
- 71dc9ec9ac7d3eee785cdc986c3daeb821381e20 and later · before ee438c492b2e0705d819ac0e25d04fae758d8f8faffected · git
- 71dc9ec9ac7d3eee785cdc986c3daeb821381e20 and later · before faf332a10372390ce65d0b803888f4b25a388335affected · git
- 71dc9ec9ac7d3eee785cdc986c3daeb821381e20 and later · before 676f03760ca1d69c2470cef36c44dc152494b47caffected · git
- 71dc9ec9ac7d3eee785cdc986c3daeb821381e20 and later · before 0dab92484474587b82e8e0455839eaf5ac7bf894affected · git
- 6.1.63 and later · before 6.1.149affected · semver
- before 6.3not affected · semver
- 6.1.149 and later · up to and including 6.1.*not affected · semver
- 6.6.103 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 |
|---|---|---|---|
| AlmaLinux:8 | bpftool | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-abi-stablelists | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-core | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-cross-headers | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-debug | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-debug-core | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-debug-devel | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules-extra | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-devel | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-doc | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-headers | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-modules | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-modules-extra | before 4.18.0-553.84.1.el8_10 | 4.18.0-553.84.1.el8_10 |
| AlmaLinux:8 | kernel-rt | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-core | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-debug | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-core | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-devel | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-devel | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
| AlmaLinux:8 | kernel-rt-modules | before 4.18.0-553.84.1.rt7.425.el8_10 | 4.18.0-553.84.1.rt7.425.el8_10 |
+96
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-2025-39716Sep 5, 2025 · parisc: Revise __get_user() to probe user read access22Monitor
- ← EarlierCVE-2025-39717Sep 5, 2025 · open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE31Monitor
- Later →CVE-2025-39719Sep 5, 2025 · iio: imu: bno055: fix OOB access of hw_xlate array28Monitor
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 | 0dab92484474587b82e8e0455839eaf5ac7bf894 | Vendor (CNA) |
| Linux Linux | 6.1.149 | Vendor (CNA) |
| Linux Linux | 676f03760ca1d69c2470cef36c44dc152494b47c | Vendor (CNA) |
| Linux Linux | 969b06bd8b7560efb100a34227619e7d318fbe05 | Vendor (CNA) |
| Linux Linux | ee438c492b2e0705d819ac0e25d04fae758d8f8f | Vendor (CNA) |
| Linux Linux | faf332a10372390ce65d0b803888f4b25a388335 | Vendor (CNA) |
| azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 | 6.6.104.2-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| almalinux:bpftool | 4.18.0-553.84.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel | 4.18.0-553.84.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-core | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-debug | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-debug-core | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-debug-devel | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-debug-modules | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-debug-modules-extra | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-devel | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-modules | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-rt-modules-extra | 4.18.0-553.84.1.rt7.425.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| debian:linux | 6.1.153-1 · Debian:12 | Package registry (OSV) |
| red hat:bpftool-debuginfo | 0:7.3.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-64k-debug-debuginfo | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-64k-debug-devel | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-64k-debug-devel-matched | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-64k-debuginfo | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-64k-devel | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-64k-devel-matched | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-debug-debuginfo | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-debug-devel | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
| red hat:kernel-debug-devel-matched | 0:5.14.0-427.96.1.el9_4 · Red Hat:rhel_eus:9.4::appstream | Package registry (OSV) |
+3
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.
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.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- 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
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
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
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (6 more)Show less
- git.kernel.org/stable/c/676f03760ca1d69c2470cef36c44dc152494b47c
- git.kernel.org/stable/c/969b06bd8b7560efb100a34227619e7d318fbe05
- git.kernel.org/stable/c/ee438c492b2e0705d819ac0e25d04fae758d8f8f
- git.kernel.org/stable/c/faf332a10372390ce65d0b803888f4b25a388335
- lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- cert-portal.siemens.com/productcert/html/ssa-032379.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.