CVE-2020-8617

CVE-2020-8617 is a high-severity vulnerability in Isc Bind with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 93% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-617.

Key facts

Description

Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.

Frequently asked questions

What is CVE-2020-8617?
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.
How severe is CVE-2020-8617?
CVE-2020-8617 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-2020-8617 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 93% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-8617?
CVE-2020-8617 primarily affects Isc Bind. In total, 25 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-8617?
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-2020-8617 published?
CVE-2020-8617 was published on 2020-05-19 and last updated on 2026-06-17.

References

Affected products (25)

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