How severe is CVE-2018-12249?

CVE-2018-12249 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-12249 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-12249?

CVE-2018-12249 primarily affects Mruby. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-12249?

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

When was CVE-2018-12249 published?

CVE-2018-12249 was published on 2018-06-12 and last updated on 2026-06-17.

CVE-2018-12249

CVE-2018-12249 is a high-severity vulnerability in Mruby with a CVSS 3.x base score of 7.5. 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-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Mruby
Published: 2018-06-12
Last modified: 2026-06-17

Description

An issue was discovered in mruby 1.4.1. There is a NULL pointer dereference in mrb_class_real because "class BasicObject" is not properly supported in class.c.

Frequently asked questions

What is CVE-2018-12249?: An issue was discovered in mruby 1.4.1. There is a NULL pointer dereference in mrb_class_real because "class BasicObject" is not properly supported in class.c.
How severe is CVE-2018-12249?: CVE-2018-12249 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-12249 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-12249?: CVE-2018-12249 primarily affects Mruby. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-12249?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-12249 published?: CVE-2018-12249 was published on 2018-06-12 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:mruby:mruby:1.4.1:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

More vulnerabilities in Mruby

CVE-2022-1286 — Critical (CVSS 9.8): heap-buffer-overflow in mrb_vm_exec in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary…
CVE-2022-1276 — Critical (CVSS 9.8): Out-of-bounds Read in mrb_get_args in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary code execution if…
CVE-2022-1212 — Critical (CVSS 9.8): Use-After-Free in str_escape in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary code…
CVE-2022-0631 — Critical (CVSS 9.8): Heap-based Buffer Overflow in Homebrew mruby prior to 3.2.
CVE-2022-0570 — Critical (CVSS 9.8): Heap-based Buffer Overflow in Homebrew mruby prior to 3.2.
CVE-2022-0080 — Critical (CVSS 9.8): mruby is vulnerable to Heap-based Buffer Overflow

All CVEs affecting Mruby →

Other CWE-476 (NULL Pointer Dereference) vulnerabilities

CVE-2022-36648 — Critical (CVSS 10.0): The hardware emulation in the of_dpa_cmd_add_l2_flood of rocker device model in QEMU, as used in 7.0.0 and earlier,…
CVE-2020-14500 — Critical (CVSS 10.0): Secomea GateManager all versions prior to 9.2c, An attacker can send a negative value and overwrite arbitrary data.
CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
CVE-2026-31436 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix possible wrong descriptor…

Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →