How severe is CVE-2018-5503?

CVE-2018-5503 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-2018-5503 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-5503?

CVE-2018-5503 affects F5 Big-ip Policy Enforcement Manager. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-5503?

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-2018-5503 published?

CVE-2018-5503 was published on 2018-03-22 and last updated on 2026-06-17.

CVE-2018-5503

CVE-2018-5503 is a high-severity vulnerability in F5 Big-ip Policy Enforcement Manager 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: F5 Big-ip Policy Enforcement Manager
Published: 2018-03-22
Last modified: 2026-06-17

Description

On F5 BIG-IP versions 13.0.0 - 13.1.0.3 or 12.0.0 - 12.1.3.1, TMM may restart when processing a specifically crafted page through a virtual server with an associated PEM policy that has content insertion as an action.

Frequently asked questions

What is CVE-2018-5503?: On F5 BIG-IP versions 13.0.0 - 13.1.0.3 or 12.0.0 - 12.1.3.1, TMM may restart when processing a specifically crafted page through a virtual server with an associated PEM policy that has content insertion as an action.
How severe is CVE-2018-5503?: CVE-2018-5503 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-2018-5503 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-5503?: CVE-2018-5503 affects F5 Big-ip Policy Enforcement Manager. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-5503?: 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-2018-5503 published?: CVE-2018-5503 was published on 2018-03-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*

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