How severe is CVE-2021-22873?

CVE-2021-22873 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-22873 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 66% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-22873?

CVE-2021-22873 affects Revive-adserver Revive Adserver. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-22873?

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

When was CVE-2021-22873 published?

CVE-2021-22873 was published on 2021-01-26 and last updated on 2026-06-17.

CVE-2021-22873

CVE-2021-22873 is a medium-severity vulnerability in Revive-adserver Revive Adserver with a CVSS 3.x base score of 6.1. Its EPSS exploit-prediction score of 66% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 5.8
EPSS exploit prediction: 66% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Revive-adserver Revive Adserver
Published: 2021-01-26
Last modified: 2026-06-17

Description

Revive Adserver before 5.1.0 is vulnerable to open redirects via the `dest`, `oadest`, and/or `ct0` parameters of the lg.php and ck.php delivery scripts. Such open redirects had previously been available by design to allow third party ad servers to track such metrics when delivering ads. However, third party click tracking via redirects is not a viable option anymore, leading to such open redirect functionality being removed and reclassified as a vulnerability.

Frequently asked questions

What is CVE-2021-22873?: Revive Adserver before 5.1.0 is vulnerable to open redirects via the `dest`, `oadest`, and/or `ct0` parameters of the lg.php and ck.php delivery scripts. Such open redirects had previously been available by design to allow third party ad servers to track such metrics when delivering ads. However, third party click tracking via redirects is not a viable option anymore, leading to such open redirect functionality being removed and reclassified as a vulnerability.
How severe is CVE-2021-22873?: CVE-2021-22873 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-22873 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 66% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22873?: CVE-2021-22873 affects Revive-adserver Revive Adserver. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-22873?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-22873 published?: CVE-2021-22873 was published on 2021-01-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:revive-adserver:revive_adserver:*:*:*:*:*:*:*:*

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CVE-2017-5830 — Critical (CVSS 9.8): Revive Adserver before 4.0.1 allows remote attackers to execute arbitrary code via serialized data in the cookies…
CVE-2016-9470 — Critical (CVSS 9.0): Revive Adserver before 3.2.5 and 4.0.0 suffers from Reflected File Download. `www/delivery/asyncspc.php` was vulnerable…
CVE-2026-50741 — High (CVSS 8.8): Bypass to the fix for CVE-2026-34916. Variants of such vectors have been also reported by phucrio and offsetmd. The fix…
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Other CWE-601 (Open Redirect) vulnerabilities

CVE-2018-3774 — Critical (CVSS 10.0): Incorrect parsing in url-parse <1.4.3 returns wrong hostname which leads to multiple vulnerabilities such as SSRF, Open…
CVE-2019-25282 — Critical (CVSS 9.8): V-SOL GPON/EPON OLT Platform v2.03 contains an open redirect vulnerability in the script that allows attackers to…
CVE-2020-36912 — Critical (CVSS 9.8): Plexus anblick Digital Signage Management 3.1.13 contains an open redirect vulnerability in the 'PantallaLogin' script…
CVE-2025-43526 — Critical (CVSS 9.8): This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac…
CVE-2025-55031 — Critical (CVSS 9.8): Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An…
CVE-2024-22891 — Critical (CVSS 9.8): Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link.

Browse all CWE-601 (Open Redirect) vulnerabilities →