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CVE Record

CVE-2022-50655: ppp: associate skb with a device at tx

In the Linux kernel, the following vulnerability has been resolved: ppp: associate skb with a device at tx Syzkaller triggered flow dissector warning with the following: r0 = openat$ppp(0xffffffffffffff9c, &(0x7f0000000000), 0xc0802, 0x0) ioctl$PPPIOCNEWUNIT(r0, 0xc004743e, &(0x7f00000000c0)) ioctl$PPPIOCSACTIVE(r0, 0x40107446, &(0x7f0000000240)={0x2, &(0x7f0000000180)=[{0x20, 0x0, 0x0, 0xfffff034}, {0x6}]}) pwritev(r0, &(0x7f0000000040)=[{&(0x7f0000000140)='\x00!', 0x2}], 0x1, 0x0, 0x0) [ 9.485814] WARNING: CPU: 3 PID: 329 at net/core/flow_dissector.c:1016 __skb_flow_dissect+0x1ee0/0x1fa0 [ 9.485929] skb_get_poff+0x53/0xa0 [ 9.485937] bpf_skb_get_pay_offset+0xe/0x20 [ 9.485944] ? ppp_send_frame+0xc2/0x5b0 [ 9.485949] ? _raw_spin_unlock_irqrestore+0x40/0x60 [ 9.485958] ? __ppp_xmit_process+0x7a/0xe0 [ 9.485968] ? ppp_xmit_process+0x5b/0xb0 [ 9.485974] ? ppp_write+0x12a/0x190 [ 9.485981] ? do_iter_write+0x18e/0x2d0 [ 9.485987] ? __import_iovec+0x30/0x130 [ 9.485997] ? do_pwritev+0x1b6/0x240 [ 9.486016] ? trace_hardirqs_on+0x47/0x50 [ 9.486023] ? __x64_sys_pwritev+0x24/0x30 [ 9.486026] ? do_syscall_64+0x3d/0x80 [ 9.486031] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd Flow dissector tries to find skb net namespace either via device or via socket. Neigher is set in ppp_send_frame, so let's manually use ppp->dev.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2022-50655 is a Linux kernel PPP networking bug found by Syzkaller. The issue can trigger a kernel warning because transmitted PPP packets lacked an associated device context. Public sources do not provide a CVSS score, confirmed security impact, or evidence of active exploitation.

Executive priority

Handle through normal kernel patch management unless PPP is widely used on exposed or high-availability systems. The urgency is constrained by missing CVSS, missing impact detail, and no cited active exploitation.

Technical view

In ppp_send_frame, skb objects could reach the flow dissector without a device or socket set, leaving the dissector unable to determine the network namespace. The kernel fix associates the skb with ppp->dev during transmit. The published trace shows a local PPP interaction causing a flow_dissector warning.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions with PPP functionality present or used. The source bundle lists Linux kernel versions around 4.20 through 6.2 and references multiple stable fixes, but vendor-specific package impact must be verified.

Exploitation context

No CISA KEV listing or cited source indicates active exploitation. The provided evidence is a Syzkaller-generated local kernel warning involving PPP ioctls and write activity, not a public exploit or demonstrated business-impacting attack.

Researcher notes

The core fix is behavioral: set skb->dev to ppp->dev before flow dissection paths need namespace context. Public data does not state confidentiality, integrity, or availability impact. Treat exploitability and privilege requirements as unconfirmed from the supplied sources.

Mitigation direction

  • Apply Linux kernel updates from your distribution or kernel vendor.
  • Confirm the update includes one of the referenced stable kernel fixes.
  • If PPP is unnecessary, ask your vendor whether disabling PPP is appropriate.
  • Track vendor advisories for CVSS, affected packages, and backport status.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and endpoints.
  • Identify systems using PPP or loading PPP-related kernel components.
  • Compare installed kernels against vendor advisories and referenced stable commits.
  • Review kernel logs for PPP or flow_dissector warnings.
  • Validate remediation by confirming the patched kernel is running after reboot.
Prepared
Confidence
medium
Sources
8

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

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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CVE-2022-50655 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
0Timeline events
0ADP providers
7Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxd58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9unaffected
LinuxLinux4.20, 0, 5.4.229, 5.10.163, 5.15.86, 6.0.16, 6.1.2, 6.2affected
Weakness

CWE details

No CWE listed

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