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CVE-2026-88833

Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service

6.5 MediumFix available

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Attack profile

How easy it is to exploit

Attack vector
Adjacent network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.19%Unchanged since Oct 14, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.5

Busybox: busybox: udhcpc integer underflow in dhcp packet length calculation causes denial of service

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
CVE-2026-88833
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-191
Updated
2026-11-02
EUVDEUVD-2026-98897 6.5

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
EUVD-2026-98897
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-hg7w-cw6w-99w3 6.5

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client...

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
GHSA-hg7w-cw6w-99w3
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-191
Updated
2026-11-02
NVD 6.5

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
CVE-2026-88833
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-191
Updated
2026-11-02
OSVBELL-CVE-2026-88833 6.5
Record
BELL-CVE-2026-88833
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2026-88833 6.5

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
DEBIAN-CVE-2026-88833
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-88833 6.5

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
UBUNTU-CVE-2026-88833
CVSS 3.1
6.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVAZL-108321 No score

CVE-2026-88833 affecting package busybox 1.36.1-28

A flaw was found in BusyBox's udhcpc DHCP client. When processing raw DHCP packets, the client replaces the validated packet length with an attacker-controlled value from the IP header without re-validating the minimum size. This leads to an integer underflow when subtracting header sizes, causing a subsequent memory copy with a massively oversized length. An attacker on the same network segment can send a specially crafted packet to crash the DHCP client, resulting in denial of service and loss of network connectivity.

Record
AZL-108321
Updated
2026-11-05
OSVopenSUSE-SU-2026:12376-1 No score

busybox-1.38.0-4.1 on GA media

These are all security issues fixed in the busybox-1.38.0-4.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:12376-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
busybox
Azure Linux:3
through 1.36.1-28 None known
busybox
Alpaquita:23
1.35.0-r29 up to 1.35.0-r42
1.35.0-r42
busybox
Alpaquita:25
1.37.0-r20 up to 1.37.0-r29
1.37.0-r29
busybox
Alpaquita:stream
1.36.1-r1 up to 1.38.0-r6
1.38.0-r6
busybox
BellSoft Hardened Containers:23
1.35.0-r29 up to 1.35.0-r42
1.35.0-r42
busybox
BellSoft Hardened Containers:25
1.37.0-r20 up to 1.37.0-r29
1.37.0-r29
busybox
BellSoft Hardened Containers:stream
1.36.1-r1 up to 1.38.0-r6
1.38.0-r6
busybox
Debian:12
All versions, plus listed versions
1:1.35.0-41:1.35.0-4+deb12u11:1.36.0-1~exp11:1.36.1-11:1.36.1-2
Show 23 moreShow less
1:1.36.1-31:1.36.1-3.11:1.36.1-41:1.36.1-51:1.36.1-61:1.36.1-6~exp.11:1.36.1-71:1.36.1-81:1.36.1-91:1.37.0-11:1.37.0-101:1.37.0-10.11:1.37.0-21:1.37.0-31:1.37.0-41:1.37.0-51:1.37.0-61:1.37.0-71:1.37.0-81:1.37.0-91:1.38.0-11:1.38.0-21:1.38.0-3
None known
busybox
Debian:13
All versions, plus listed versions
1:1.37.0-101:1.37.0-10.11:1.37.0-61:1.37.0-71:1.37.0-8
Show 4 moreShow less
1:1.37.0-91:1.38.0-11:1.38.0-21:1.38.0-3
None known
busybox
Debian:14
All versions, plus listed versions
1:1.37.0-101:1.37.0-10.11:1.37.0-61:1.37.0-71:1.37.0-8
Show 4 moreShow less
1:1.37.0-91:1.38.0-11:1.38.0-21:1.38.0-3
None known
Show 9 moreShow less
Affected packages
PackageAffectedFixed
busybox
Ubuntu:Pro:14.04:LTS
All versions, plus listed versions
1:1.20.0-8.1ubuntu11:1.20.0-9ubuntu11:1.20.0-9ubuntu21:1.21.0-1ubuntu11:1.21.0-1ubuntu1.41:1.21.0-1ubuntu1.4+esm1
None known
busybox
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
1:1.22.0-15ubuntu11:1.22.0-15ubuntu1.41:1.22.0-15ubuntu1.4+esm11:1.22.0-15ubuntu1.4+esm2
None known
busybox
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
1:1.22.0-19ubuntu21:1.27.2-1ubuntu31:1.27.2-1ubuntu41:1.27.2-2ubuntu21:1.27.2-2ubuntu3
Show 5 moreShow less
1:1.27.2-2ubuntu3.11:1.27.2-2ubuntu3.21:1.27.2-2ubuntu3.31:1.27.2-2ubuntu3.41:1.27.2-2ubuntu3.4+esm1
None known
busybox
Ubuntu:20.04:LTS
All versions, plus listed versions
1:1.30.1-4ubuntu41:1.30.1-4ubuntu51:1.30.1-4ubuntu61:1.30.1-4ubuntu6.11:1.30.1-4ubuntu6.21:1.30.1-4ubuntu6.31:1.30.1-4ubuntu6.41:1.30.1-4ubuntu6.5
None known
busybox
Ubuntu:22.04:LTS
All versions, plus listed versions
1:1.30.1-6ubuntu31:1.30.1-7ubuntu11:1.30.1-7ubuntu21:1.30.1-7ubuntu31:1.30.1-7ubuntu3.1
None known
busybox
Ubuntu:24.04:LTS
All versions, plus listed versions
1:1.36.1-3ubuntu11:1.36.1-6ubuntu11:1.36.1-6ubuntu31:1.36.1-6ubuntu3.1
None known
busybox
Ubuntu:26.10
All versions, plus listed versions
1:1.37.0-7ubuntu11:1.37.0-10.1ubuntu21:1.37.0-10.1ubuntu31:1.38.0-3ubuntu11:1.38.0-3ubuntu31:1.38.0-3ubuntu4
None known
busybox
Ubuntu:26.04:LTS
All versions, plus listed versions
1:1.37.0-4ubuntu11:1.37.0-7ubuntu1
None known
busybox
openSUSE:Tumbleweed
From an advisory covering 8 CVEs
before 1.38.0-4.1
1.38.0-4.1

History

History
RecordedChangedSources
affected
factsOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-88833 is a medium vulnerability (CVSS 6.5) in Red Hat Hardened Images, published October 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 8th percentile. Fixed in busybox 1.35.0-r42.

References

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