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CVE Record

CVE-2022-48809: net: fix a memleak when uncloning an skb dst and its metadata

In the Linux kernel, the following vulnerability has been resolved: net: fix a memleak when uncloning an skb dst and its metadata When uncloning an skb dst and its associated metadata, a new dst+metadata is allocated and later replaces the old one in the skb. This is helpful to have a non-shared dst+metadata attached to a specific skb. The issue is the uncloned dst+metadata is initialized with a refcount of 1, which is increased to 2 before attaching it to the skb. When tun_dst_unclone returns, the dst+metadata is only referenced from a single place (the skb) while its refcount is 2. Its refcount will never drop to 0 (when the skb is consumed), leading to a memory leak. Fix this by removing the call to dst_hold in tun_dst_unclone, as the dst+metadata refcount is already 1.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2022-48809 is a Linux kernel memory leak in network packet routing metadata handling. Under affected code paths, memory may not be released after packet processing. The public record does not provide CVSS, exploitation evidence, or business-specific impact. Treat it as a stability and availability risk for Linux systems, especially those using relevant networking features.

Executive priority

Schedule remediation through normal kernel patch cycles unless affected systems show instability or are critical network infrastructure. There is no public active-exploitation signal in the provided sources, but memory leaks in kernel networking can become availability issues if left unpatched.

Technical view

The bug is in Linux kernel networking: tun_dst_unclone allocates an uncloned dst plus metadata object, then increments a reference count that is already initialized to one. After attachment to the skb, the object remains over-referenced and is not freed when the skb is consumed, causing a memory leak. Kernel stable commits remove the unnecessary dst_hold call.

Likely exposure

Exposure is limited to Linux kernels containing the affected networking code. The source bundle lists Linux as affected and references stable fixes across multiple kernel branches. Exact distribution package exposure depends on vendor backports, so validate against your OS vendor advisories and installed kernel build.

Exploitation context

No cited source or KEV entry indicates active exploitation. The public description supports a memory leak condition, which could affect availability if repeatedly triggered, but the provided sources do not describe attack prerequisites, remote reachability, or a practical exploit path.

Researcher notes

The record lacks CVSS, CWE, and exploitation detail. Analysis should focus on identifying kernels with the vulnerable tun_dst_unclone implementation and confirming whether downstream vendors backported the stable fix. Avoid assuming exploitability beyond the documented memory leak.

Mitigation direction

  • Update affected Linux kernels using distribution or vendor-supported packages.
  • Confirm the relevant stable kernel fix is included or backported.
  • Prioritize internet-facing, high-throughput, or network-intensive Linux systems.
  • If patching is delayed, monitor kernel memory behavior and service stability.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and containers hosts.
  • Compare installed kernels with vendor advisories and referenced stable commits.
  • Check change logs for the tun_dst_unclone memory leak fix.
  • Review monitoring for unexplained kernel memory growth or network-service instability.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2022-48809 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxfc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404, fc4099f17240767554ff3a73977acb78ef615404unaffected
LinuxLinux4.3, 0, 4.9.302, 4.14.267, 4.19.230, 5.4.180, 5.10.101, 5.15.24, 5.16.10, 5.17affected
Weakness

CWE details

No CWE listed

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