How severe is CVE-2020-12242?

CVE-2020-12242 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-12242 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-12242?

CVE-2020-12242 affects Valvesoftware Source. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-12242?

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-2020-12242 published?

CVE-2020-12242 was published on 2020-04-27 and last updated on 2026-06-17.

CVE-2020-12242

CVE-2020-12242 is a high-severity vulnerability in Valvesoftware Source with a CVSS 3.x base score of 7.8. 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-78.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Valvesoftware Source
Published: 2020-04-27
Last modified: 2026-06-17

Description

Valve Source allows local users to gain privileges by writing to the /tmp/hl2_relaunch file, which is later executed in the context of a different user account.

Frequently asked questions

What is CVE-2020-12242?: Valve Source allows local users to gain privileges by writing to the /tmp/hl2_relaunch file, which is later executed in the context of a different user account.
How severe is CVE-2020-12242?: CVE-2020-12242 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-12242 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12242?: CVE-2020-12242 affects Valvesoftware Source. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-12242?: 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-2020-12242 published?: CVE-2020-12242 was published on 2020-04-27 and last updated on 2026-06-17.

References

https://0xem.ma/cve/2020/04/28/Source-hl2-relaunch-exec.html

Affected products (1)

cpe:2.3:a:valvesoftware:source:-:*:*:*:*:*:*:*

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