CVE-2026-97964: ppp_synctty: ensure a writeable skb header
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: 0.17% (FIRST EPSS).
- Fixed version: Linux Linux 0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e, 15d0a6c9a42df2d745c37510dba828f6dbe60d9f, 25e03eeead2c49748c7582dfb64c205f93a42d00; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e, 15d0a6c9a42df2d745c37510dba828f6dbe60d9f, 25e03eeead2c49748c7582dfb64c205f93a42d00; 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: ppp_synctty: ensure a writeable skb header ppp_sync_txmunge() checks headroom before prepending the address and control bytes, but does not ensure that the skb header is writable. A received skb can reach this function through PPP channel bridging without passing through ppp_start_xmit(), which calls skb_cow_head(). For example, a PPPoE frame may share its buffer with a clone queued to an AF_PACKET socket. If it is bridged to a synchronous tty channel, the address/control bytes can overwrite data still visible to that socket. Use skb_cow_head() to ensure both sufficient headroom and a writable header.
- Published
- Sep 25, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.1% · 6th percentile
- CWE
- —
Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
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
- 5.11affected
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before 25e03eeead2c49748c7582dfb64c205f93a42d00affected · git
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before a256f9925288ef47de8febed5c38d5cc21340211affected · git
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before 7953946f68262a8bb137aa101249adef6e029652affected · git
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before 3af7797fbabc84992e0ca5ad2bc0ca8537d053efaffected · git
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before 0996c3e6bcc6ae08cb371ed43648c9f7f748ae6eaffected · git
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before 15d0a6c9a42df2d745c37510dba828f6dbe60d9faffected · git
- 4cf476ced45d7f12df30a68e833b263e7a2202d1 and later · before 8aaeb56aff2a557a88f83ae866da2c91ad247e59affected · git
- before 5.11not affected · semver
- 5.15.222 and later · up to and including 5.15.*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 6.12.111-1~deb12u1 | 6.12.111-1~deb12u1 |
| Debian:13 | linux | before 6.12.111-1 | 6.12.111-1 |
| Debian:14 | linux | before 7.2.7-1 | 7.2.7-1 |
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-2026-97962Sep 25, 2026 · net/mlx5e: Move representor vnic reporter to eswitch devlink port0Monitor
- ← EarlierCVE-2026-97963Sep 25, 2026 · net: stmmac: initialize ptp_lock at probe time0Monitor
- Later →CVE-2026-97965Sep 25, 2026 · vxlan: initialize _md in vxlan_xmit_one()0Monitor
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 | 0996c3e6bcc6ae08cb371ed43648c9f7f748ae6e | Vendor (CNA) |
| Linux Linux | 15d0a6c9a42df2d745c37510dba828f6dbe60d9f | Vendor (CNA) |
| Linux Linux | 25e03eeead2c49748c7582dfb64c205f93a42d00 | Vendor (CNA) |
| Linux Linux | 3af7797fbabc84992e0ca5ad2bc0ca8537d053ef | Vendor (CNA) |
| Linux Linux | 7953946f68262a8bb137aa101249adef6e029652 | Vendor (CNA) |
| Linux Linux | 8aaeb56aff2a557a88f83ae866da2c91ad247e59 | Vendor (CNA) |
| Linux Linux | a256f9925288ef47de8febed5c38d5cc21340211 | 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 | 6.12.111-1 · Debian:13 | Package registry (OSV) |
| debian:linux-6.12 | 6.12.111-1~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.
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).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-1184 · Sep 28, 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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (6 more)Show less
- git.kernel.org/stable/c/15d0a6c9a42df2d745c37510dba828f6dbe60d9f
- git.kernel.org/stable/c/25e03eeead2c49748c7582dfb64c205f93a42d00
- git.kernel.org/stable/c/3af7797fbabc84992e0ca5ad2bc0ca8537d053ef
- git.kernel.org/stable/c/7953946f68262a8bb137aa101249adef6e029652
- git.kernel.org/stable/c/8aaeb56aff2a557a88f83ae866da2c91ad247e59
- git.kernel.org/stable/c/a256f9925288ef47de8febed5c38d5cc21340211
Vendor advisories and official records. Exploit/PoC links are deliberately left out.