CVE-2026-63888Network attack vector

Remote kernel compromise via iSCSI Text PDUs

Published Jul 19, 2026 · Updated Jul 19, 2026

Memory corruption in the Linux kernel LIO iSCSI target allows remote attackers to crash or compromise the host via crafted Text PDUs. iscsit_handle_text_cmd() passes a DataDigest-expanded length to CRC32C, reading four bytes beyond text_in, and leaves cmd->text_in_ptr dangling after a bad-digest free so later handling frees it again. Reachability requires an enabled network-facing LIO iSCSI target; unauthenticated discovery can negotiate CRC32C, while the double-free additionally requires ErrorRecoveryLevel above zero and a follow-up request or teardown.

CVSS severity9.8
Critical
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in the Linux kernel LIO iSCSI target allows remote attackers to crash or compromise the host via crafted Text PDUs. iscsit_handle_text_cmd() passes a DataDigest-expanded length to CRC32C, reading four bytes beyond text_in, and leaves cmd->text_in_ptr dangling after a bad-digest free so later handling frees it again. Reachability requires an enabled network-facing LIO iSCSI target; unauthenticated discovery can negotiate CRC32C, while the double-free additionally requires ErrorRecoveryLevel above zero and a follow-up request or teardown.

The record

CVE
CVE-2026-63888
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=3.1
  2. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <5118ea225fe63b44207ba88047e4866e1ea43812
  3. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <6e22a1cdcc8277af4acc43710577157b77a02c5d
  4. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <778c2ab142c625a8a8afa570e0f9b7873f445d99
  5. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <89c81d1228c00fa6dd91de6c1c5aa1ef8a7875e3
  6. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <badf178b76b0690851df00f4ca9cf2eb8eb0f963
  7. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <d3e9b79aa794f7a23e82de4d710e7d2df610e349
  8. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <ec9f19d52074a191ed1756ed4a7d39fff1a2085c
  9. Affected versionversion=e48354ce078c079996f89d715dfa44814b4eba01 <f7948af0dd03de84079dcd4dc215a69fd6fbb95d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.1; version=e48354ce078c079996f89d715dfa44814b4eba01 <5118ea225fe63b44207ba88047e4866e1ea43812; version=e48354ce078c079996f89d715dfa44814b4eba01 <6e22a1cdcc8277af4acc43710577157b77a02c5d; version=e48354ce078c079996f89d715dfa44814b4eba01 <778c2ab142c625a8a8afa570e0f9b7873f445d99; version=e48354ce078c079996f89d715dfa44814b4eba01 <89c81d1228c00fa6dd91de6c1c5aa1ef8a7875e3; version=e48354ce078c079996f89d715dfa44814b4eba01 <badf178b76b0690851df00f4ca9cf2eb8eb0f963; version=e48354ce078c079996f89d715dfa44814b4eba01 <d3e9b79aa794f7a23e82de4d710e7d2df610e349; version=e48354ce078c079996f89d715dfa44814b4eba01 <ec9f19d52074a191ed1756ed4a7d39fff1a2085c; version=e48354ce078c079996f89d715dfa44814b4eba01 <f7948af0dd03de84079dcd4dc215a69fd6fbb95d

Published CVSS scores

8.2Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
9.8Linux kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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