CVE-2026-89538: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-3r47-q2hr-fjxp
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CVSS 9.8
Published
Advisory Summary

CVE-2026-89538 is a CRITICAL (CVSS 9.8) security vulnerability vulnerability (General Security Weakness) affecting Software libraries in the Maven ecosystem. Remediation is available in the latest vendor maintenance releases.

CVE-2026-89538 at a Glance

CVE Identifier CVE-2026-89538
GHSA Identifier GHSA-3r47-q2hr-fjxp
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification General Security Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
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-2026-89538

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-2026-89538, 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 General Security Weakness. 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: SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field gss_krb5_unwrap_v2() sets buf->len to a logical length, which can be much smaller than head[0].iov_len (the allocated receive-page capacity). It then calls xdr_buf_trim() with a trim length derived from the 16-bit "extra count" (ec) field in the Kerberos v2 token header. The ec field is authenticated by the post-decrypt memcmp() against the encrypted header copy, so a randomly-mutated value is rejected. However, any peer holding a valid GSS context can legitimately encrypt a token whose ec exceeds the plaintext length. Per RFC 4121, such a token is structurally malformed. Although xdr_buf_trim() now clamps the buf->len subtraction to avoid unsigned underflow, the buffer is still left in a semantically invalid state (zero length, inconsistent iov lengths) when ec is oversized. Reject these tokens before calling xdr_buf_trim(), giving callers a well-defined GSS_S_DEFECTIVE_TOKEN error and keeping the xdr_buf internally consistent. The wrapped blob begins at a nonzero offset -- both callers pass len as offset + opaque_len -- so buf->len still counts the offset bytes that precede the blob. Compare the trim length against the remaining wrapped segment, buf->len - offset, rather than the whole buffer; comparing against buf->len alone leaves an offset-wide window in which an oversized ec passes the test and xdr_buf_trim() cuts into the bytes ahead of the blob.

References

NVD — CVE-2026-89538 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89538
git.kernel.org/stable/c/1f9856af06... WEB
https://git.kernel.org/stable/c/1f9856af065b6158271687e9788407b9573fd16f
git.kernel.org/stable/c/4abb44a29b... WEB
https://git.kernel.org/stable/c/4abb44a29bb515df6f49123848765c70fc9b5021
git.kernel.org/stable/c/880effc943... WEB
https://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6
git.kernel.org/stable/c/9fc6d6e6db... WEB
https://git.kernel.org/stable/c/9fc6d6e6db49ab55208d5dd1c424c1d0d9aa7296
git.kernel.org/stable/c/ac9efc2934... WEB
https://git.kernel.org/stable/c/ac9efc29346b6942e71f0e24a3178a9121330fab
git.kernel.org/stable/c/ad484748ee... WEB
https://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91
git.kernel.org/stable/c/b5746095b5... WEB
https://git.kernel.org/stable/c/b5746095b59f4d11f39f08751d36bbdfd1e5deac
git.kernel.org/stable/c/dfcd81ab45... WEB
https://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9

Frequently Asked Questions

What is CVE-2026-89538?
CVE-2026-89538 is a security vulnerability in Software classified as a security vulnerability vulnerability under General Security Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-89538?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-89538?
CVE-2026-89538 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-89538?
CVE-2026-89538 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-89538?
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 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3r47-q2hr-fjxp",
  "modified" : "2026-09-14T15:32:28Z",
  "published" : "2026-09-11T21:31:31Z",
  "aliases" : [ "CVE-2026-89538" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: Reject krb5 v2 wrap tokens with oversized ec field\n\ngss_krb5_unwrap_v2() sets buf->len to a logical\nlength, which can be much smaller than head[0].iov_len\n(the allocated receive-page capacity).  It then calls\nxdr_buf_trim() with a trim length derived from the 16-bit\n\"extra count\" (ec) field in the Kerberos v2 token header.\n\nThe ec field is authenticated by the post-decrypt memcmp()\nagainst the encrypted header copy, so a randomly-mutated\nvalue is rejected.  However, any peer holding a valid GSS\ncontext can legitimately encrypt a token whose ec exceeds\nthe plaintext length.  Per RFC 4121, such a token is\nstructurally malformed.\n\nAlthough xdr_buf_trim() now clamps the buf->len subtraction\nto avoid unsigned underflow, the buffer is still left in a\nsemantically invalid state (zero length, inconsistent iov\nlengths) when ec is oversized.\n\nReject these tokens before calling xdr_buf_trim(), giving\ncallers a well-defined GSS_S_DEFECTIVE_TOKEN error and\nkeeping the xdr_buf internally consistent.  The wrapped blob\nbegins at a nonzero offset -- both callers pass len as\noffset + opaque_len -- so buf->len still counts the offset\nbytes that precede the blob.  Compare the trim length\nagainst the remaining wrapped segment, buf->len - offset,\nrather than the whole buffer; comparing against buf->len\nalone leaves an offset-wide window in which an oversized ec\npasses the test and xdr_buf_trim() cuts into the bytes ahead\nof the blob.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-89538"
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  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/4abb44a29bb515df6f49123848765c70fc9b5021"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/9fc6d6e6db49ab55208d5dd1c424c1d0d9aa7296"
  }, {
    "type" : "WEB",
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  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b5746095b59f4d11f39f08751d36bbdfd1e5deac"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-11T20:19:36Z"
  }
}