Security readout for executives and security teams
Plain-English summary
CVE-2022-49871 is a Linux kernel memory leak in the TUN network driver path. A local user or process with relevant access could trigger leaked kernel memory and degrade availability over time. The source rates it medium, with high availability impact but no confidentiality or integrity impact.
Executive priority
Patch through the normal kernel maintenance process, with accelerated handling for multi-tenant or user-accessible systems. There is no source evidence of active exploitation, but the availability impact justifies timely remediation.
Technical view
The bug is in net/tun handling of napi_get_frags. After napi_gro_frags can leave entries on napi->rx_list, tun_napi_del deletes NAPI without completing pending GRO work, leaking skb allocations. The kernel fix adds napi_complete after napi_gro_frags.
Likely exposure
Exposure is mainly Linux systems running affected kernel builds where local low-privileged users or processes can exercise the TUN driver path. The bundle lists Linux kernel versions including 4.15, 4.19.267, 5.4.225, 5.10.155, 5.15.79, 6.0.9, and 6.1-era entries.
Exploitation context
The CVSS vector is local, low complexity, low privileges, no user interaction, unchanged scope, and high availability impact. The bundle does not indicate CISA KEV listing or active exploitation. Treat this as a local denial-of-service risk, not remote code execution.
Researcher notes
Evidence is limited to the CVE record and Linux stable references. The root cause is cleanup ordering around NAPI GRO fragments in tun_get_user and tun_napi_del. Validate against downstream vendor kernels because distribution backports may not match upstream version strings.
Mitigation direction
- Apply a vendor kernel update that includes the referenced upstream stable fixes.
- Check your Linux distribution advisory for exact fixed package versions.
- Prioritize hosts with untrusted local users, containers, VPNs, or TUN usage.
- Limit unnecessary access to TUN devices while awaiting vendor guidance.
Validation and detection
- Inventory Linux kernel versions across exposed fleets.
- Map kernels to vendor advisories and the referenced stable commits.
- Confirm whether TUN/TAP functionality is enabled or reachable by local users.
- Review monitoring for unexplained kernel memory growth or availability degradation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-401: Exact CWE lookup
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Open ATT&CK lookupCVE-2022-49871 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/223ef6a94e52331a6a7ef31e59921e0e82d2d40aCVE reference, Linux
- https://git.kernel.org/stable/c/a4f73f6adc53fd7a3f9771cbc89a03ef39b0b755CVE reference, Linux
- https://git.kernel.org/stable/c/3401f964028ac941425b9b2c8ff8a022539ef44aCVE reference, Linux
- https://git.kernel.org/stable/c/d7569302a7a52a9305d2fb054df908ff985553bbCVE reference, Linux
- https://git.kernel.org/stable/c/8b12a020b20a78f62bedc50f26db3bf4fadf8cb9CVE reference, Linux
- https://git.kernel.org/stable/c/1118b2049d77ca0b505775fc1a8d1909cf19a7ecCVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Release of Memory after Effective Lifetime
Missing Release of Memory after Effective Lifetime represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.