How severe is CVE-2018-6551?

CVE-2018-6551 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-6551 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-6551?

CVE-2018-6551 affects Gnu Glibc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-6551?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-6551 published?

CVE-2018-6551 was published on 2018-02-02 and last updated on 2026-06-17.

CVE-2018-6551

CVE-2018-6551 is a critical-severity vulnerability in Gnu Glibc with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Gnu Glibc
Published: 2018-02-02
Last modified: 2026-06-17

Description

The malloc implementation in the GNU C Library (aka glibc or libc6), from version 2.24 to 2.26 on powerpc, and only in version 2.26 on i386, did not properly handle malloc calls with arguments close to SIZE_MAX and could return a pointer to a heap region that is smaller than requested, eventually leading to heap corruption.

Frequently asked questions

What is CVE-2018-6551?: The malloc implementation in the GNU C Library (aka glibc or libc6), from version 2.24 to 2.26 on powerpc, and only in version 2.26 on i386, did not properly handle malloc calls with arguments close to SIZE_MAX and could return a pointer to a heap region that is smaller than requested, eventually leading to heap corruption.
How severe is CVE-2018-6551?: CVE-2018-6551 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-6551 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-6551?: CVE-2018-6551 affects Gnu Glibc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-6551?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-6551 published?: CVE-2018-6551 was published on 2018-02-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*

More vulnerabilities in Gnu Glibc

CVE-2015-0235 — Critical (CVSS 10.0): Heap-based buffer overflow in the __nss_hostname_digits_dots function in glibc 2.2, and other 2.x versions before 2.18,…
CVE-2026-5450 — Critical (CVSS 9.8): Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to version…
CVE-2023-25139 — Critical (CVSS 9.8): sprintf in the GNU C Library (glibc) 2.37 has a buffer overflow (out-of-bounds write) in some situations with a correct…
CVE-2022-23219 — Critical (CVSS 9.8): The deprecated compatibility function clnt_create in the sunrpc module of the GNU C Library (aka glibc) through 2.34…
CVE-2022-23218 — Critical (CVSS 9.8): The deprecated compatibility function svcunix_create in the sunrpc module of the GNU C Library (aka glibc) through 2.34…
CVE-2021-33574 — Critical (CVSS 9.8): The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the…

All CVEs affecting Gnu Glibc →

Other CWE-190 (Integer Overflow or Wraparound) vulnerabilities

CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-24814 — Critical (CVSS 10.0): Integer Overflow or Wraparound vulnerability in swoole swoole-src (thirdparty/hiredis modules). This vulnerability is…
CVE-2025-64721 — Critical (CVSS 10.0): Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions…
CVE-2015-5108 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2013-2555 — Critical (CVSS 10.0): Integer overflow in Adobe Flash Player before 10.3.183.75 and 11.x before 11.7.700.169 on Windows and Mac OS X, before…

Browse all CWE-190 (Integer Overflow or Wraparound) vulnerabilities →