How severe is CVE-2018-18661?

CVE-2018-18661 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-18661 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-18661?

CVE-2018-18661 primarily affects Libtiff. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-18661?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-18661 published?

CVE-2018-18661 was published on 2018-10-26 and last updated on 2026-06-17.

CVE-2018-18661

CVE-2018-18661 is a medium-severity vulnerability in Libtiff with a CVSS 3.x base score of 6.5. 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: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Libtiff
Published: 2018-10-26
Last modified: 2026-06-17

Description

An issue was discovered in LibTIFF 4.0.9. There is a NULL pointer dereference in the function LZWDecode in the file tif_lzw.c.

Frequently asked questions

What is CVE-2018-18661?: An issue was discovered in LibTIFF 4.0.9. There is a NULL pointer dereference in the function LZWDecode in the file tif_lzw.c.
How severe is CVE-2018-18661?: CVE-2018-18661 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-18661 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-18661?: CVE-2018-18661 primarily affects Libtiff. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-18661?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-18661 published?: CVE-2018-18661 was published on 2018-10-26 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:libtiff:libtiff:4.0.9:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*

More vulnerabilities in Libtiff

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