CVE-2026-31586: Software Security Vulnerability Vulnerability
HIGHCVE-2026-31586 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-416: Use After Free) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.. Remediation is available in the latest vendor maintenance releases.
CVE-2026-31586 at a Glance
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).
How to Fix CVE-2026-31586
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.
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:treeHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-31586, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:treeAnalyze 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-416: Use After Free, where the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. 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
References
Frequently Asked Questions
What is CVE-2026-31586?
Which Software versions are affected?
What version fixes CVE-2026-31586?
What is the CVSS score of CVE-2026-31586?
What CWE is associated with CVE-2026-31586?
How can I check Maven dependencies for CVE-2026-31586?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-x7q8-xcw2-7mfg",
"modified" : "2026-10-15T03:35:42Z",
"published" : "2026-04-24T15:32:34Z",
"aliases" : [ "CVE-2026-31586" ],
"details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: blk-cgroup: fix use-after-free in cgwb_release_workfn()\n\ncgwb_release_workfn() calls css_put(wb->blkcg_css) and then later accesses\nwb->blkcg_css again via blkcg_unpin_online(). If css_put() drops the last\nreference, the blkcg can be freed asynchronously (css_free_rwork_fn ->\nblkcg_css_free -> kfree) before blkcg_unpin_online() dereferences the\npointer to access blkcg->online_pin, resulting in a use-after-free:\n\n BUG: KASAN: slab-use-after-free in blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367)\n Write of size 4 at addr ff11000117aa6160 by task kworker/71:1/531\n Workqueue: cgwb_release cgwb_release_workfn\n Call Trace:\n <TASK>\n blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367)\n cgwb_release_workfn (mm/backing-dev.c:629)\n process_scheduled_works (kernel/workqueue.c:3278 kernel/workqueue.c:3385)\n\n Freed by task 1016:\n kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6246 mm/slub.c:6561)\n css_free_rwork_fn (kernel/cgroup/cgroup.c:5542)\n process_scheduled_works (kernel/workqueue.c:3302 kernel/workqueue.c:3385)\n\n** Stack based on commit 66672af7a095 (\"Add linux-next specific files\nfor 20260410\")\n\nI am seeing this crash sporadically in Meta fleet across multiple kernel\nversions. A full reproducer is available at:\nhttps://github.com/leitao/debug/blob/main/reproducers/repro_blkcg_uaf.sh\n\n(The race window is narrow. To make it easily reproducible, inject a\nmsleep(100) between css_put() and blkcg_unpin_online() in\ncgwb_release_workfn(). With that delay and a KASAN-enabled kernel, the\nreproducer triggers the splat reliably in less than a second.)\n\nFix this by moving blkcg_unpin_online() before css_put(), so the\ncgwb's CSS reference keeps the blkcg alive while blkcg_unpin_online()\naccesses it.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
} ],
"affected" : [ ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31586"
}, {
"type" : "WEB",
"url" : "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/115a5266749dcde7fe4127e8623d19c752088f69"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/1bd36e93b542d9dd020190c6607c6a3663405195"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/23acef4156c260e8598397a1a2e8b3a23e919893"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/50879a3c1faf06e661090015d59e2127255cff27"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/67cb119d32f35e32acd0393bbeb318b2bb1fdafe"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/740ba1ebb223f137ff088ab74d533a13f9167bd8"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/8f5857be99f1ed1fa80991c72449541f634626ee"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/dfc8292a1d6782c76b626315605e0585a5a18447"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/ea3af09eb87d8f8708c66747fcf1a2762902e839"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-416" ],
"severity" : "HIGH",
"github_reviewed" : false,
"github_reviewed_at" : null,
"nvd_published_at" : "2026-04-24T15:16:33Z"
}
}