Vulnerability-Lookup

FKIE_CVE-2026-31691

Vulnerability from fkie_nvd - Published: 2026-04-27 18:16 - Updated: 2026-05-06 20:49

Severity

5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: igb: remove napi_synchronize() in igb_down() When an AF_XDP zero-copy application terminates abruptly (e.g., kill -9), the XSK buffer pool is destroyed but NAPI polling continues. igb_clean_rx_irq_zc() repeatedly returns the full budget, preventing napi_complete_done() from clearing NAPI_STATE_SCHED. igb_down() calls napi_synchronize() before napi_disable() for each queue vector. napi_synchronize() spins waiting for NAPI_STATE_SCHED to clear, which never happens. igb_down() blocks indefinitely, the TX watchdog fires, and the TX queue remains permanently stalled. napi_disable() already handles this correctly: it sets NAPI_STATE_DISABLE. After a full-budget poll, __napi_poll() checks napi_disable_pending(). If set, it forces completion and clears NAPI_STATE_SCHED, breaking the loop that napi_synchronize() cannot. napi_synchronize() was added in commit 41f149a285da ("igb: Fix possible panic caused by Rx traffic arrival while interface is down"). napi_disable() provides stronger guarantees: it prevents further scheduling and waits for any active poll to exit. Other Intel drivers (ixgbe, ice, i40e) use napi_disable() without a preceding napi_synchronize() in their down paths. Remove redundant napi_synchronize() call and reorder napi_disable() before igb_set_queue_napi() so the queue-to-NAPI mapping is only cleared after polling has fully stopped.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/27f5997686ee7fb7ac01be72b2010f168a3409fc	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/4700471775746058c962ded6e659bf908fd76e13	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b1e067240379f950a0022208e0685f3465c211cb	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0

JSON

To clipboard

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nigb: remove napi_synchronize() in igb_down()\n\nWhen an AF_XDP zero-copy application terminates abruptly (e.g., kill -9),\nthe XSK buffer pool is destroyed but NAPI polling continues.\nigb_clean_rx_irq_zc() repeatedly returns the full budget, preventing\nnapi_complete_done() from clearing NAPI_STATE_SCHED.\n\nigb_down() calls napi_synchronize() before napi_disable() for each queue\nvector. napi_synchronize() spins waiting for NAPI_STATE_SCHED to clear,\nwhich never happens. igb_down() blocks indefinitely, the TX watchdog\nfires, and the TX queue remains permanently stalled.\n\nnapi_disable() already handles this correctly: it sets NAPI_STATE_DISABLE.\nAfter a full-budget poll, __napi_poll() checks napi_disable_pending(). If\nset, it forces completion and clears NAPI_STATE_SCHED, breaking the loop\nthat napi_synchronize() cannot.\n\nnapi_synchronize() was added in commit 41f149a285da (\"igb: Fix possible\npanic caused by Rx traffic arrival while interface is down\").\nnapi_disable() provides stronger guarantees: it prevents further\nscheduling and waits for any active poll to exit.\nOther Intel drivers (ixgbe, ice, i40e) use napi_disable() without a\npreceding napi_synchronize() in their down paths.\n\nRemove redundant napi_synchronize() call and reorder napi_disable()\nbefore igb_set_queue_napi() so the queue-to-NAPI mapping is only\ncleared after polling has fully stopped."
    }
  ],
  "id": "CVE-2026-31691",
  "lastModified": "2026-05-06T20:49:04.757",
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          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
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}

CVE-2026-31691 (GCVE-0-2026-31691)

Vulnerability from cvelistv5 – Published: 2026-04-27 17:34 – Updated: 2026-05-11 22:13

Title

igb: remove napi_synchronize() in igb_down()

Summary

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/4700471775746058c…
https://git.kernel.org/stable/c/27f5997686ee7fb7a…
https://git.kernel.org/stable/c/b1e067240379f950a…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 2c6196013f84651772388a86dfd4bb033d0c0d45 , < 4700471775746058c962ded6e659bf908fd76e13 (git) Affected: 2c6196013f84651772388a86dfd4bb033d0c0d45 , < 27f5997686ee7fb7ac01be72b2010f168a3409fc (git) Affected: 2c6196013f84651772388a86dfd4bb033d0c0d45 , < b1e067240379f950a0022208e0685f3465c211cb (git)
Linux	Linux	Affected: 6.14 Unaffected: 0 , < 6.14 (semver) Unaffected: 6.18.23 , ≤ 6.18.* (semver) Unaffected: 6.19.13 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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FKIE_CVE-2026-31691

CVE-2026-31691 (GCVE-0-2026-31691)

Tags

Sightings

Nomenclature