CVE-2026-23340: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-27rj-chmq-rh6r
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CVSS 7.8
CWE-362 CWE-416
Published
Advisory Summary

CVE-2026-23340 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-23340 at a Glance

CVE Identifier CVE-2026-23340
GHSA Identifier GHSA-27rj-chmq-rh6r
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-23340

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-23340, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'), where the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In the Linux kernel, the following vulnerability has been resolved: net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs When shrinking the number of real tx queues, netif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush qdiscs for queues which will no longer be used. qdisc_reset_all_tx_gt() currently serializes qdisc_reset() with qdisc_lock(). However, for lockless qdiscs, the dequeue path is serialized by qdisc_run_begin/end() using qdisc->seqlock instead, so qdisc_reset() can run concurrently with __qdisc_run() and free skbs while they are still being dequeued, leading to UAF. This can easily be reproduced on e.g. virtio-net by imposing heavy traffic while frequently changing the number of queue pairs: iperf3 -ub0 -c $peer -t 0 & while :; do ethtool -L eth0 combined 1 ethtool -L eth0 combined 2 done With KASAN enabled, this leads to reports like: BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760 ... Call Trace: <TASK> ... __qdisc_run+0x133f/0x1760 __dev_queue_xmit+0x248f/0x3550 ip_finish_output2+0xa42/0x2110 ip_output+0x1a7/0x410 ip_send_skb+0x2e6/0x480 udp_send_skb+0xb0a/0x1590 udp_sendmsg+0x13c9/0x1fc0 ... </TASK> Allocated by task 1270 on cpu 5 at 44.558414s: ... alloc_skb_with_frags+0x84/0x7c0 sock_alloc_send_pskb+0x69a/0x830 __ip_append_data+0x1b86/0x48c0 ip_make_skb+0x1e8/0x2b0 udp_sendmsg+0x13a6/0x1fc0 ... Freed by task 1306 on cpu 3 at 44.558445s: ... kmem_cache_free+0x117/0x5e0 pfifo_fast_reset+0x14d/0x580 qdisc_reset+0x9e/0x5f0 netif_set_real_num_tx_queues+0x303/0x840 virtnet_set_channels+0x1bf/0x260 [virtio_net] ethnl_set_channels+0x684/0xae0 ethnl_default_set_doit+0x31a/0x890 ... Serialize qdisc_reset_all_tx_gt() against the lockless dequeue path by taking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the serialization model already used by dev_reset_queue(). Additionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state reflects an empty queue, avoiding needless re-scheduling.

References

NVD — CVE-2026-23340 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23340
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-457936.html
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-784472.html
git.kernel.org/stable/c/5bb27ad54d... WEB
https://git.kernel.org/stable/c/5bb27ad54d12de67e457d7d251198e361bef835e
git.kernel.org/stable/c/5bc4e69306... WEB
https://git.kernel.org/stable/c/5bc4e69306ed7ae02232eb4c0b23ed621a26d504
git.kernel.org/stable/c/7594467c49... WEB
https://git.kernel.org/stable/c/7594467c49bfc2f4644dee0415ac2290db11fa0d
git.kernel.org/stable/c/7f083faf59... WEB
https://git.kernel.org/stable/c/7f083faf59d14c04e01ec05a7507f036c965acf8
git.kernel.org/stable/c/8314944cc3... WEB
https://git.kernel.org/stable/c/8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb
git.kernel.org/stable/c/c69df4e052... WEB
https://git.kernel.org/stable/c/c69df4e0524f8de8e176ba389acd83e85f5f49d0
git.kernel.org/stable/c/dbd58b0730... WEB
https://git.kernel.org/stable/c/dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750

Frequently Asked Questions

What is CVE-2026-23340?
CVE-2026-23340 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-23340?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-23340?
CVE-2026-23340 has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-23340?
CVE-2026-23340 is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') (The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.).
How can I check Maven dependencies for CVE-2026-23340?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "id" : "GHSA-27rj-chmq-rh6r",
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  "published" : "2026-03-25T12:30:23Z",
  "aliases" : [ "CVE-2026-23340" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs\n\nWhen shrinking the number of real tx queues,\nnetif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush\nqdiscs for queues which will no longer be used.\n\nqdisc_reset_all_tx_gt() currently serializes qdisc_reset() with\nqdisc_lock(). However, for lockless qdiscs, the dequeue path is\nserialized by qdisc_run_begin/end() using qdisc->seqlock instead, so\nqdisc_reset() can run concurrently with __qdisc_run() and free skbs\nwhile they are still being dequeued, leading to UAF.\n\nThis can easily be reproduced on e.g. virtio-net by imposing heavy\ntraffic while frequently changing the number of queue pairs:\n\n  iperf3 -ub0 -c $peer -t 0 &\n  while :; do\n    ethtool -L eth0 combined 1\n    ethtool -L eth0 combined 2\n  done\n\nWith KASAN enabled, this leads to reports like:\n\n  BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760\n  ...\n  Call Trace:\n   <TASK>\n   ...\n   __qdisc_run+0x133f/0x1760\n   __dev_queue_xmit+0x248f/0x3550\n   ip_finish_output2+0xa42/0x2110\n   ip_output+0x1a7/0x410\n   ip_send_skb+0x2e6/0x480\n   udp_send_skb+0xb0a/0x1590\n   udp_sendmsg+0x13c9/0x1fc0\n   ...\n   </TASK>\n\n  Allocated by task 1270 on cpu 5 at 44.558414s:\n   ...\n   alloc_skb_with_frags+0x84/0x7c0\n   sock_alloc_send_pskb+0x69a/0x830\n   __ip_append_data+0x1b86/0x48c0\n   ip_make_skb+0x1e8/0x2b0\n   udp_sendmsg+0x13a6/0x1fc0\n   ...\n\n  Freed by task 1306 on cpu 3 at 44.558445s:\n   ...\n   kmem_cache_free+0x117/0x5e0\n   pfifo_fast_reset+0x14d/0x580\n   qdisc_reset+0x9e/0x5f0\n   netif_set_real_num_tx_queues+0x303/0x840\n   virtnet_set_channels+0x1bf/0x260 [virtio_net]\n   ethnl_set_channels+0x684/0xae0\n   ethnl_default_set_doit+0x31a/0x890\n   ...\n\nSerialize qdisc_reset_all_tx_gt() against the lockless dequeue path by\ntaking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the\nserialization model already used by dev_reset_queue().\n\nAdditionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state\nreflects an empty queue, avoiding needless re-scheduling.",
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    "type" : "CVSS_V3",
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    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
  }, {
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    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
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    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-457936.html"
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    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"
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