CVE-2026-89542: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-h928-qw5v-x6vj
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CVSS 9.8
Published
Advisory Summary

CVE-2026-89542 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-2026-89542 at a Glance

CVE Identifier CVE-2026-89542
GHSA Identifier GHSA-h928-qw5v-x6vj
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-2026-89542

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-2026-89542, 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: harden gss_krb5_unwrap_v2 against short tokens gss_krb5_unwrap_v2() reads the EC and RRC header fields at ptr+4 and ptr+6 before validating that the token is at least GSS_KRB5_TOK_HDR_LEN (16) bytes long, and its rotate_left() helper passes buf->len - base to xdr_buf_subsegment() without verifying that base <= buf->len. When a caller hands in a sub-16-byte token, or a token whose declared len leaves base past the end of the buffer, three distinct failures follow: gss_krb5_unwrap_v2(offset, len, buf) ptr = buf->head[0].iov_base + offset ec = *(ptr + 4) /* OOB read on short head */ rrc = *(ptr + 6) /* OOB read on short head */ rotate_left(offset + 16, buf, rrc) xdr_buf_subsegment(buf, &subbuf, base, buf->len - base) /* u32 wrap when base > len */ _rotate_left(&subbuf, shift) shift %= buf->len /* divide-by-zero when base == len */ After decryption, the cleanup arithmetic has the same shape: movelen = min_t(unsigned int, buf->head[0].iov_len, len); movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip; BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen > buf->head[0].iov_len); The BUG_ON re-adds the value just subtracted, so it reduces to min(A, B) > A and is permanently false; it cannot catch the unsigned underflow of movelen, which then drives a ~UINT_MAX-byte memmove(). Add four defense-in-depth guards inside the unwrap core so it is safe regardless of what its callers validate: - reject tokens with len - offset < GSS_KRB5_TOK_HDR_LEN before touching ptr+4/ptr+6; - bail from rotate_left() when buf->len <= base, covering both the underflow and zero-length cases; - return early from _rotate_left() when buf->len is zero, so the shift %= buf->len modulo cannot fault; - replace the dead BUG_ON with a live check that returns GSS_S_DEFECTIVE_TOKEN before the movelen subtraction.

References

NVD — CVE-2026-89542 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89542
git.kernel.org/stable/c/075d7cfc4d... WEB
https://git.kernel.org/stable/c/075d7cfc4df8c54cb202ba8b28420370c03ba9b6
git.kernel.org/stable/c/299d281c72... WEB
https://git.kernel.org/stable/c/299d281c7225ded15b28cb861a98d818d82787fc
git.kernel.org/stable/c/6959297aaa... WEB
https://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888
git.kernel.org/stable/c/806584a4b6... WEB
https://git.kernel.org/stable/c/806584a4b67a7233870c33e5b8f872e76dd02988
git.kernel.org/stable/c/84ddbc8d08... WEB
https://git.kernel.org/stable/c/84ddbc8d084c0251d534f14f5d1a7da05be56404
git.kernel.org/stable/c/a7894e1057... WEB
https://git.kernel.org/stable/c/a7894e10572d53eb10109b8d07459cc8d3435811
git.kernel.org/stable/c/dddcb0f4b7... WEB
https://git.kernel.org/stable/c/dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087
git.kernel.org/stable/c/f2591660e0... WEB
https://git.kernel.org/stable/c/f2591660e0eb263c9415bf0d0bb1b111e62df7a4

Frequently Asked Questions

What is CVE-2026-89542?
CVE-2026-89542 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-2026-89542?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-89542?
CVE-2026-89542 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-2026-89542?
CVE-2026-89542 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-89542?
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-h928-qw5v-x6vj",
  "modified" : "2026-09-14T15:32:28Z",
  "published" : "2026-09-11T21:31:31Z",
  "aliases" : [ "CVE-2026-89542" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: harden gss_krb5_unwrap_v2 against short tokens\n\ngss_krb5_unwrap_v2() reads the EC and RRC header fields at ptr+4 and\nptr+6 before validating that the token is at least GSS_KRB5_TOK_HDR_LEN\n(16) bytes long, and its rotate_left() helper passes buf->len - base\nto xdr_buf_subsegment() without verifying that base <= buf->len. When\na caller hands in a sub-16-byte token, or a token whose declared len\nleaves base past the end of the buffer, three distinct failures follow:\n\n    gss_krb5_unwrap_v2(offset, len, buf)\n      ptr = buf->head[0].iov_base + offset\n      ec  = *(ptr + 4)              /* OOB read on short head */\n      rrc = *(ptr + 6)              /* OOB read on short head */\n      rotate_left(offset + 16, buf, rrc)\n        xdr_buf_subsegment(buf, &subbuf,\n                           base, buf->len - base)   /* u32 wrap when base > len */\n        _rotate_left(&subbuf, shift)\n          shift %= buf->len         /* divide-by-zero when base == len */\n\nAfter decryption, the cleanup arithmetic has the same shape:\n\n    movelen = min_t(unsigned int, buf->head[0].iov_len, len);\n    movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;\n    BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >\n                                            buf->head[0].iov_len);\n\nThe BUG_ON re-adds the value just subtracted, so it reduces to\nmin(A, B) > A and is permanently false; it cannot catch the unsigned\nunderflow of movelen, which then drives a ~UINT_MAX-byte memmove().\n\nAdd four defense-in-depth guards inside the unwrap core so it is safe\nregardless of what its callers validate:\n\n  - reject tokens with len - offset < GSS_KRB5_TOK_HDR_LEN before\n    touching ptr+4/ptr+6;\n  - bail from rotate_left() when buf->len <= base, covering both the\n    underflow and zero-length cases;\n  - return early from _rotate_left() when buf->len is zero, so the\n    shift %= buf->len modulo cannot fault;\n  - replace the dead BUG_ON with a live check that returns\n    GSS_S_DEFECTIVE_TOKEN before the movelen subtraction.",
  "severity" : [ {
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    "url" : "https://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888"
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    "url" : "https://git.kernel.org/stable/c/f2591660e0eb263c9415bf0d0bb1b111e62df7a4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-11T20:19:37Z"
  }
}