CVE-2021-47308Network attack vector

Disclosure and interruption via unchecked FC-4 type

Published May 21, 2024 · Updated Aug 5, 2026

Out-of-bounds read in Linux kernel libfc allows remote attackers to disclose data or interrupt service through a crafted PRLI response. The fc_rport_prli_resp() handler uses the response's untrusted spp_type value to index fc_passive_prov without checking it against FC_FC4_PROV_SIZE. Reachability requires an active Fibre Channel libfc path and control of a peer response; an invalid FC-4 type causes a provider-array overread that exposes memory or destabilizes kernel service.

CVSS severity6.5
Medium
EPSS probability1.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Linux kernel libfc allows remote attackers to disclose data or interrupt service through a crafted PRLI response. The fc_rport_prli_resp() handler uses the response's untrusted spp_type value to index fc_passive_prov without checking it against FC_FC4_PROV_SIZE. Reachability requires an active Fibre Channel libfc path and control of a peer response; an invalid FC-4 type causes a provider-array overread that exposes memory or destabilizes kernel service.

The record

CVE
CVE-2021-47308
Published
May 21, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <0fe70c15f9435bb3c50954778245d62ee38b0e03
  2. Affected versionversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <44651522941c623e20882b3b443f23f77de1ea8b
  3. Affected versionversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <4921b1618045ffab71b1050bf0014df3313a2289
  4. Affected versionversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <8511293e643a18b248510ae5734e4f360754348c
  5. Affected versionversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <a4a54c54af2516caa9c145015844543cfc84316a
  6. Affected versionversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <b27c4577557045f1ab3cdfeabfc7f3cd24aca1fe
  7. Affected versionversion=4.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=386b97b43c0c9e0d878eec7ea1db16af22b036ae <0fe70c15f9435bb3c50954778245d62ee38b0e03; version=386b97b43c0c9e0d878eec7ea1db16af22b036ae <44651522941c623e20882b3b443f23f77de1ea8b; version=386b97b43c0c9e0d878eec7ea1db16af22b036ae <4921b1618045ffab71b1050bf0014df3313a2289; version=386b97b43c0c9e0d878eec7ea1db16af22b036ae <8511293e643a18b248510ae5734e4f360754348c; version=386b97b43c0c9e0d878eec7ea1db16af22b036ae <a4a54c54af2516caa9c145015844543cfc84316a; version=386b97b43c0c9e0d878eec7ea1db16af22b036ae <b27c4577557045f1ab3cdfeabfc7f3cd24aca1fe; version=4.10

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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