CVE-2026-98591: bpf: Fix bounds check for skb-backed dynptrs
Noroxi assessment
Priority: Monitor (action score 0/100)
- 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: 0.20% (FIRST EPSS).
- Fixed version: Linux Linux 1196903a27cac5c929c7517e987a8d159f20c5e5, 1b923538598be768e9f2f258a77a083d00e0c78b, 37877a24758068742fef687a7cf5362360dde1d1; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 1196903a27cac5c929c7517e987a8d159f20c5e5, 1b923538598be768e9f2f258a77a083d00e0c78b, 37877a24758068742fef687a7cf5362360dde1d1; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1 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: bpf: Fix bounds check for skb-backed dynptrs The skb_pointer_if_linear() function checks whether a memory region of length len starting at offset off into the skb is in the linear area, and returns a pointer to the region if so. The check currently subtracts between skb_headlen and offset of the check, and since skb_headlen is unsigned the subtraction can underflow. This causes the bounds check to spuriously pass and generate an arbitrary pointer of the form *(skb->data + off). The only user of this helper is currently skb-backed BPF dynptr code. Returning the wrong pointer leads to the dynptr erroneously being backed with invalid memory. Ensure the subtraction cannot underflow, and fail the check if it would. Use u64 arithmetic to also prevent overflow when calculating (skb_headlen(skb) - off) since off is unsigned.
- Published
- Oct 18, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.2% · 10th percentile
- CWE
- —
Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
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
- 6.6affected
- 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and later · before 1b923538598be768e9f2f258a77a083d00e0c78baffected · git
- 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and later · before 37877a24758068742fef687a7cf5362360dde1d1affected · git
- 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and later · before 1196903a27cac5c929c7517e987a8d159f20c5e5affected · git
- 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and later · before 39ffceaddb10753eac12785dba6ac0673860b4acaffected · git
- 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and later · before ed6eec97b534979dcf28b40c389cee57bd6561d4affected · git
- before 6.6not affected · semver
- 6.6.158 and later · up to and including 6.6.*not affected · semver
- 6.12.112 and later · up to and including 6.12.*not affected · semver
- 6.18.55 and later · up to and including 6.18.*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-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 7.2.9-1 | 7.2.9-1 |
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-2026-98589Oct 18, 2026 · bpf: Reject pkt arguments in mutating subprogs0Monitor
- ← EarlierCVE-2026-98590Oct 18, 2026 · bpf: Fix bpf_sock context code generation0Monitor
- Later →CVE-2026-98592Oct 18, 2026 · net: spacemit: clear TX descriptor on fragment mapping failure0Monitor
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 | 1196903a27cac5c929c7517e987a8d159f20c5e5 | Vendor (CNA) |
| Linux Linux | 1b923538598be768e9f2f258a77a083d00e0c78b | Vendor (CNA) |
| Linux Linux | 37877a24758068742fef687a7cf5362360dde1d1 | Vendor (CNA) |
| Linux Linux | 39ffceaddb10753eac12785dba6ac0673860b4ac | Vendor (CNA) |
| Linux Linux | ed6eec97b534979dcf28b40c389cee57bd6561d4 | Vendor (CNA) |
| azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 | 6.6.159.1-1 · Release Notes | Microsoft (MSRC) |
| debian:linux | 6.12.113-1 · Debian:13 | 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
- TodayNov 6, 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).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-1351 · Oct 19, 2026(Linux Kernel Güvenlik Bildirimi)
Technical details
No CVSS vector for this record, so attack conditions can't be derived.
Weakness class (CWE)
—
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
- Exploit maturity— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.