CVE-2021-252177.4HighCWE-119

CVE-2021-25217: A buffer overrun in lease file parsing code can be used to exploit a common vulnerability shared by dhcpd and dhclient

ISC · ISC DHCP

Vendor fix available · Affected: ISC DHCP · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

6.1%probability of exploitation in the next 30 days

93rd percentile

050100

Higher than 93% of scored CVEs

7.4HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

In ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16, ISC DHCP 4.4.0 -> 4.4.2 (Other branches of ISC DHCP (i.e., releases in the 4.0.x series or lower and releases in the 4.3.x series) are beyond their End-of-Life (EOL) and no longer supported by ISC. From inspection it is clear that the defect is also present in releases from those series, but they have not been officially tested for the vulnerability), The outcome of encountering the defect while reading a lease that will trigger it varies, according to: the component being affected (i.e., dhclient or dhcpd) whether the package was built as a 32-bit or 64-bit binary whether the compiler flag -fstack-protection-strong was used when compiling In dhclient, ISC has not successfully reproduced the error on a 64-bit system. However, on a 32-bit system it is possible to cause dhclient to crash when reading an improper lease, which could cause network connectivity problems for an affected system due to the absence of a running DHCP client process. In dhcpd, when run in DHCPv4 or DHCPv6 mode: if the dhcpd server binary was built for a 32-bit architecture AND the -fstack-protection-strong flag was specified to the compiler, dhcpd may exit while parsing a lease file containing an objectionable lease, resulting in lack of service to clients. Additionally, the offending lease and the lease immediately following it in the lease database may be improperly deleted. if the dhcpd server binary was built for a 64-bit architecture OR if the -fstack-protection-strong compiler flag was NOT specified, the crash will not occur, but it is possible for the offending lease and the lease which immediately followed it to be improperly deleted.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

ISC · ISC DHCPfrom 4.1 ESV before 4.1-ESV-R16-P1; from 4.4 before 4.4.2-P1

On the Atlas

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Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Memory Buffer Bounds · Memory Corruption
Vendor: ISC
Published: May 2021
Band: Possible (1 to 10%), May 2021

CoverageNo articles yet

No CyberSIXT article names CVE-2021-25217 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.