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NVD / CVE Program· CNA Linux

CVE-2026-93105: esp: do not unref managed frag pages in esp_ssg_unref()

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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).
  • 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 1ad6456898f6e6cf58be83bdb607acb1119a9cd1, 201bdf10ae92e7cbd524adf8c0323e2a963d5fd7, 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 1ad6456898f6e6cf58be83bdb607acb1119a9cd1, 201bdf10ae92e7cbd524adf8c0323e2a963d5fd7, 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes 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: esp: do not unref managed frag pages in esp_ssg_unref() esp_ssg_unref() releases the page references held on the source scatterlist after the AEAD operation completes. It calls skb_page_unref() on every frag page for an out-of-place transform (req->src != req->dst), and in the error path of esp_output_tail() (already_unref == true) on the request's own scatterlist. This is wrong when the skb carries managed frags (SKBFL_MANAGED_FRAG_REFS). Managed frags are owned by a zerocopy ubuf and the skb does not hold a per-frag page reference; io_uring SEND_ZC with a registered buffer attaches the bvec pages this way via io_sg_from_iter(). The rest of the stack honours this invariant: skb_release_data() skips the per-frag unref when SKBFL_MANAGED_FRAG_REFS is set, and skb_zcopy_managed() is the guard used at the other unref sites. esp_ssg_unref() is missing that guard, so for a managed-frag skb it drops a page reference the skb never acquired. This can underflow the page reference count and free a page that is still in use. Guard the function with skb_zcopy_managed() so both unref paths are skipped for managed-frag skbs, matching skb_release_data().

Published
Sep 17, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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.

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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.

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Affected 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

    • 4.11affected
    • cac2661c53f35cbe651bef9b07026a5a05ab8ce0 and later · before cb375965800d474c0281a2e92c43c724fce9f463affected · git
    • cac2661c53f35cbe651bef9b07026a5a05ab8ce0 and later · before 201bdf10ae92e7cbd524adf8c0323e2a963d5fd7affected · git
    • cac2661c53f35cbe651bef9b07026a5a05ab8ce0 and later · before 3ec55f0c8a6a543cf660584d1346e11f6311ee59affected · git
    • cac2661c53f35cbe651bef9b07026a5a05ab8ce0 and later · before 1ad6456898f6e6cf58be83bdb607acb1119a9cd1affected · git
    • cac2661c53f35cbe651bef9b07026a5a05ab8ce0 and later · before 26b6b14c7a0368e317a1e9fb5144ebe6f8d495cfaffected · git
    • cac2661c53f35cbe651bef9b07026a5a05ab8ce0 and later · before 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80affected · git
    • before 4.11not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.160 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.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-93103Sep 17, 2026 · RDMA/hfi1: Preserve unit 0 on allocation failure
    0Monitor
  • ← EarlierCVE-2026-93104Sep 17, 2026 · RDMA/rvt: Return NULL after port allocation failure
    0Monitor
  • Later →CVE-2026-93106Sep 17, 2026 · crash_dump: release keyring reference at the correct time
    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 / packageFixed versionSource
Linux Linux1ad6456898f6e6cf58be83bdb607acb1119a9cd1Vendor (CNA)
Linux Linux201bdf10ae92e7cbd524adf8c0323e2a963d5fd7Vendor (CNA)
Linux Linux21697720ff43b8dfa25b8e8d9ca7f56f4597fc80Vendor (CNA)
Linux Linux26b6b14c7a0368e317a1e9fb5144ebe6f8d495cfVendor (CNA)
Linux Linux3ec55f0c8a6a543cf660584d1346e11f6311ee59Vendor (CNA)
Linux Linuxcb375965800d474c0281a2e92c43c724fce9f463Vendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.06.6.161.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.12.115-2 · Debian:13Package registry (OSV)
debian:linux7.2.6-1 · Debian:14Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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
high · data or configuration can be modified
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
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/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.

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records