How severe is CVE-2024-8508?

CVE-2024-8508 has a CVSS 3.x base score of 5.3, rated medium 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 low.

Is CVE-2024-8508 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-8508?

CVE-2024-8508 primarily affects Nlnetlabs Unbound. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-8508?

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

Does CVE-2024-8508 have an EU (EUVD) identifier?

Yes. CVE-2024-8508 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-49228.

When was CVE-2024-8508 published?

CVE-2024-8508 was published on 2024-10-03 and last updated on 2026-06-17.

CVE-2024-8508

CVE-2024-8508 is a medium-severity vulnerability in Nlnetlabs Unbound with a CVSS 3.x base score of 5.3. 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-1284.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-49228
Weakness: CWE-1284
Affected product: Nlnetlabs Unbound
Published: 2024-10-03
Last modified: 2026-06-17

Description

NLnet Labs Unbound up to and including version 1.21.0 contains a vulnerability when handling replies with very large RRsets that it needs to perform name compression for. Malicious upstreams responses with very large RRsets can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. The vulnerability can be exploited by a malicious actor querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. Unbound version 1.21.1 introduces a hard limit on the number of name compression calculations it is willing to do per packet. Packets that need more compression will result in semi-compressed packets or truncated packets, even on TCP for huge messages, to avoid locking the CPU for long. This change should not affect normal DNS traffic.

Frequently asked questions

What is CVE-2024-8508?: NLnet Labs Unbound up to and including version 1.21.0 contains a vulnerability when handling replies with very large RRsets that it needs to perform name compression for. Malicious upstreams responses with very large RRsets can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. The vulnerability can be exploited by a malicious actor querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. Unbound version 1.21.1 introduces a hard limit on the number of name compression calculations it is willing to do per packet. Packets that need more compression will result in semi-compressed packets or truncated packets, even on TCP for huge messages, to avoid locking the CPU for long. This change should not affect normal DNS traffic.
How severe is CVE-2024-8508?: CVE-2024-8508 has a CVSS 3.x base score of 5.3, rated medium 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 low.
Is CVE-2024-8508 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-8508?: CVE-2024-8508 primarily affects Nlnetlabs Unbound. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-8508?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-8508 have an EU (EUVD) identifier?: Yes. CVE-2024-8508 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-49228.
When was CVE-2024-8508 published?: CVE-2024-8508 was published on 2024-10-03 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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