CVE-2020-17437

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-12-11 · updated 2026-06-17
Weakness: CWE-787

Description

An issue was discovered in uIP 1.0, as used in Contiki 3.0 and other products. When the Urgent flag is set in a TCP packet, and the stack is configured to ignore the urgent data, the stack attempts to use the value of the Urgent pointer bytes to separate the Urgent data from the normal data, by calculating the offset at which the normal data should be present in the global buffer. However, the length of this offset is not checked; therefore, for large values of the Urgent pointer bytes, the data pointer can point to memory that is way beyond the data buffer in uip_process in uip.c.

Affected products

Open-Iscsi Project Open-Iscsi: through 2.1.7
Siemens Sentron 3Va Com100 Firmware: before 4.4.1 — fixed in 4.4.1
Siemens Sentron 3Va Com800 Firmware: before 4.4.1 — fixed in 4.4.1
Siemens Sentron 3Va Dsp800 Firmware: before 4.0 — fixed in 4.0
Siemens Sentron Pac2200 Clp Firmware: all versions
Siemens Sentron Pac2200 Firmware: before 3.2.2 — fixed in 3.2.2
Siemens Sentron Pac3200 Firmware: before 2.4.7 — fixed in 2.4.7
Siemens Sentron Pac3200T Firmware: before 3.2.2 — fixed in 3.2.2
Siemens Sentron Pac3220 Firmware: before 3.2.0 — fixed in 3.2.0
Siemens Sentron Pac4200 Firmware: before 2.3.0 — fixed in 2.3.0
Uip Project Uip: through 1.0

How to fix

Upgrade to a fixed version: Siemens Sentron 3Va Com100 Firmware 4.4.1; Siemens Sentron 3Va Com800 Firmware 4.4.1; Siemens Sentron 3Va Dsp800 Firmware 4.0; Siemens Sentron Pac2200 Firmware 3.2.2; Siemens Sentron Pac3200 Firmware 2.4.7; Siemens Sentron Pac3200T Firmware 3.2.2; Siemens Sentron Pac3220 Firmware 3.2.0; Siemens Sentron Pac4200 Firmware 2.3.0. Check the vendor advisory for mitigations.

References

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