CVE-2021-39921
published 2021-11-19CVE-2021-39921: NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture…
PriorityP337high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
3.24%
86.9th percentile
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
Affected
15 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | wireshark | < wireshark 3.6.0-1 (bookworm) | wireshark 3.6.0-1 (bookworm) |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| msrc | cbl2_wireshark_3.4.14-1_on_cbl_mariner_2.0 | — | — |
| msrc | cbl_mariner_2.0_arm | — | — |
| msrc | cbl_mariner_2.0_x64 | — | — |
| wireshark | wireshark | >= 0 < 3.4.10-0+deb11u1 | 3.4.10-0+deb11u1 |
| wireshark | wireshark | >= 0 < 3.6.0-1 | 3.6.0-1 |
| wireshark | wireshark | >= 0 < 3.6.0-1 | 3.6.0-1 |
| wireshark | wireshark | >= 0 < 3.6.0-1 | 3.6.0-1 |
| wireshark | wireshark | 3.2.0 – 3.2.17 | — |
| wireshark | wireshark | 3.4.0 – 3.4.9 | — |
| wireshark_foundation | wireshark | — | — |
| wireshark_foundation | wireshark | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:N/I:N/A:P
osv7.5HIGH
vendor_debian7.5HIGH
vendor_msrc7.5HIGH
vendor_redhat7.5HIGH
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Red Hat
wireshark: modbus dissector crash
vendor_redhat·2021-11-17·CVSS 7.5
CVE-2021-39921 [HIGH] CWE-476 wireshark: modbus dissector crash
wireshark: modbus dissector crash
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
A NULL pointer exception flaw was found in Wireshark. A process failure on crafted or malformed input in the Modbus dissector can cause a denial of service via a packet injection or crafted capture file.
Package: wireshark (Red Hat Enterprise Linux 6) - Not affected
Package: wireshark (Red Hat Enterprise Linux 7) - Not affected
Package: wireshark (Red Hat Enterprise Linux 8) - Not affected
Package: wireshark (Red Hat Enterprise Linux 9) - Not affected
Microsoft
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
vendor_msrc·2021-11-09·CVSS 7.5
CVE-2021-39921 [HIGH] CWE-476 NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mari
Debian
CVE-2021-39921: wireshark - NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3...
vendor_debian·2021·CVSS 7.5
CVE-2021-39921 [HIGH] CVE-2021-39921: wireshark - NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3...
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
Scope: local
bookworm: resolved (fixed in 3.6.0-1)
bullseye: resolved (fixed in 3.4.10-0+deb11u1)
forky: resolved (fixed in 3.6.0-1)
sid: resolved (fixed in 3.6.0-1)
trixie: resolved (fixed in 3.6.0-1)
GHSA
GHSA-5rpm-jh2v-38p6: NULL pointer exception in the Modbus dissector in Wireshark 3
ghsa_unreviewed·2021-11-20
CVE-2021-39921 [HIGH] CWE-476 GHSA-5rpm-jh2v-38p6: NULL pointer exception in the Modbus dissector in Wireshark 3
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
OSV
CVE-2021-39921: NULL pointer exception in the Modbus dissector in Wireshark 3
osv·2021-11-19·CVSS 7.5
CVE-2021-39921 [HIGH] CVE-2021-39921: NULL pointer exception in the Modbus dissector in Wireshark 3
NULL pointer exception in the Modbus dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39921.jsonhttps://gitlab.com/wireshark/wireshark/-/issues/17703https://lists.debian.org/debian-lts-announce/2021/12/msg00015.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A6AJFIYIHS3TYDD2EBYBJ5KKE52X34BJ/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YEWTIRMC2MFQBZ2O5M4CJHJM4JPBHLXH/https://security.gentoo.org/glsa/202210-04https://www.debian.org/security/2021/dsa-5019https://www.wireshark.org/security/wnpa-sec-2021-14.htmlhttps://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39921.jsonhttps://gitlab.com/wireshark/wireshark/-/issues/17703https://lists.debian.org/debian-lts-announce/2021/12/msg00015.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A6AJFIYIHS3TYDD2EBYBJ5KKE52X34BJ/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YEWTIRMC2MFQBZ2O5M4CJHJM4JPBHLXH/https://security.gentoo.org/glsa/202210-04https://www.debian.org/security/2021/dsa-5019https://www.wireshark.org/security/wnpa-sec-2021-14.html
2021-11-19
Published