How severe is CVE-2021-43099?

CVE-2021-43099 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-43099 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-2021-43099?

CVE-2021-43099 affects Diyhi Bbs. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43099?

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

When was CVE-2021-43099 published?

CVE-2021-43099 was published on 2022-03-28 and last updated on 2026-06-17.

CVE-2021-43099

CVE-2021-43099 is a medium-severity vulnerability in Diyhi Bbs with a CVSS 3.x base score of 4.9. 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-22.

Key facts

Severity: Medium (CVSS 3.x base score 4.9)
CVSS v2: 4.0
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Diyhi Bbs
Published: 2022-03-28
Last modified: 2026-06-17

Description

An Archive Extraction (AKA "Zip Slip) vulnerability exists in bbs 5.3 in the UpgradeNow function in UpgradeManageAction.java, which unzips the arbitrary upladed zip file without checking filenames. The vulnerability is exploited using a specially crafted archive that holds directory traversal filenames (e.g. ../../evil.exe).

Frequently asked questions

What is CVE-2021-43099?: An Archive Extraction (AKA "Zip Slip) vulnerability exists in bbs 5.3 in the UpgradeNow function in UpgradeManageAction.java, which unzips the arbitrary upladed zip file without checking filenames. The vulnerability is exploited using a specially crafted archive that holds directory traversal filenames (e.g. ../../evil.exe).
How severe is CVE-2021-43099?: CVE-2021-43099 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-43099 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-2021-43099?: CVE-2021-43099 affects Diyhi Bbs. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43099?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43099 published?: CVE-2021-43099 was published on 2022-03-28 and last updated on 2026-06-17.

References

https://github.com/diyhi/bbs/issues/51

Affected products (1)

cpe:2.3:a:diyhi:bbs:5.3:*:*:*:*:*:*:*

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