kernel: challenge ACK counter information disclosure.
Published Aug 6, 2016
4.8
MEDIUMCVSS 3.0
EPSS 15.07%
Description
net/ipv4/tcp_input.c in the Linux kernel before 4.7 does not properly determine the rate of challenge ACK segments, which makes it easier for remote attackers to hijack TCP sessions via a blind in-window attack.
Affected products
No data.
No data.
Red Hat Enterprise Linux 6
kernel-0:2.6.32-642.4.2.el6
Fixed · RHSA-2016:1664
Red Hat Enterprise Linux 6.5 Advanced Update Support
kernel-0:2.6.32-431.73.2.el6
Fixed · RHSA-2016:1814
Red Hat Enterprise Linux 6.6 Extended Update Support
kernel-0:2.6.32-504.52.1.el6
Fixed · RHSA-2016:1939
Red Hat Enterprise Linux 6.7 Extended Update Support
kernel-0:2.6.32-573.34.1.el6
Fixed · RHSA-2016:1815
Red Hat Enterprise Linux 7
kernel-0:3.10.0-327.28.3.el7
Fixed · RHSA-2016:1633
Red Hat Enterprise Linux 7
kernel-rt-0:3.10.0-327.28.3.rt56.235.el7
Fixed · RHSA-2016:1632
Red Hat Enterprise Linux 7.1 Extended Update Support
kernel-0:3.10.0-229.40.1.ael7b
Fixed · RHSA-2016:1657
Red Hat Enterprise MRG 2
kernel-rt-1:3.10.0-327.rt56.195.el6rt
Fixed · RHSA-2016:1631
Red Hat Enterprise Linux 4
kernel
Not affected
Red Hat Enterprise Linux 5
kernel
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel-0:2.6.32-642.4.2.el6 | Fixed | RHSA-2016:1664 |
| Red Hat Enterprise Linux 6.5 Advanced Update Support | kernel-0:2.6.32-431.73.2.el6 | Fixed | RHSA-2016:1814 |
| Red Hat Enterprise Linux 6.6 Extended Update Support | kernel-0:2.6.32-504.52.1.el6 | Fixed | RHSA-2016:1939 |
| Red Hat Enterprise Linux 6.7 Extended Update Support | kernel-0:2.6.32-573.34.1.el6 | Fixed | RHSA-2016:1815 |
| Red Hat Enterprise Linux 7 | kernel-0:3.10.0-327.28.3.el7 | Fixed | RHSA-2016:1633 |
| Red Hat Enterprise Linux 7 | kernel-rt-0:3.10.0-327.28.3.rt56.235.el7 | Fixed | RHSA-2016:1632 |
| Red Hat Enterprise Linux 7.1 Extended Update Support | kernel-0:3.10.0-229.40.1.ael7b | Fixed | RHSA-2016:1657 |
| Red Hat Enterprise MRG 2 | kernel-rt-1:3.10.0-327.rt56.195.el6rt | Fixed | RHSA-2016:1631 |
| Red Hat Enterprise Linux 4 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 5 | kernel | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 4 and 5.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
AV:N/AC:M/Au:N/C:N/I:P/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (18 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 15.07% (0.15073) | 96.63th | v5 (v2026.06.15) |
| Jun 15, 2026 | 15.86% (0.15855) | 96.45th | v5 (v2026.06.15) |
| Apr 18, 2026 | 51.99% (0.51991) | 97.92th | v4 (v2025.03.14) |
| Apr 1, 2026 | 29.16% (0.29161) | 96.55th | v4 (v2025.03.14) |
| Feb 20, 2026 | 33.30% (0.33300) | 96.80th | v4 (v2025.03.14) |
| Jul 20, 2025 | 34.41% (0.34409) | 96.80th | v4 (v2025.03.14) |
| Jun 10, 2025 | 33.30% (0.33300) | 96.67th | v4 (v2025.03.14) |
| Apr 9, 2025 | 29.16% (0.29161) | 96.19th | v4 (v2025.03.14) |
| Mar 30, 2025 | 58.61% (0.58608) | 98.03th | v4 (v2025.03.14) |
| Mar 29, 2025 | 63.36% (0.63360) | 97.74th | v4 (v2025.03.14) |
| Mar 28, 2025 | 58.61% (0.58608) | 98.03th | v4 (v2025.03.14) |
| Mar 17, 2025 | 64.34% (0.64341) | 98.29th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.45% (0.00446) | 75.80th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.45% (0.00446) | 74.23th | v3 (v2023.03.01) |
| Jul 10, 2023 | 0.45% (0.00446) | 71.51th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.31% (0.00314) | 65.51th | v3 (v2023.03.01) |
| Mar 6, 2023 | 35.72% (0.35720) | 97.84th | v2 (v2022.01.01) |
| Feb 4, 2022 | 35.72% (0.35720) | 96.93th | v2 (v2022.01.01) |
References (36)
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=75ff39ccc1bd5d3c455b6822ab09e533c551f758 x_refsource_CONFIRMIssue TrackingPatch
- http://lwn.net/Articles/696868/
- http://rhn.redhat.com/errata/RHSA-2016-1631.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1632.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1633.html vendor-advisoryx_refsource_REDHAT
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- http://rhn.redhat.com/errata/RHSA-2016-1664.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1814.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1815.html vendor-advisoryx_refsource_REDHAT
- http://rhn.redhat.com/errata/RHSA-2016-1939.html vendor-advisoryx_refsource_REDHAT
- http://source.android.com/security/bulletin/2016-10-01.html x_refsource_CONFIRMThird Party Advisory
- http://www.openwall.com/lists/oss-security/2016/07/12/2 mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html x_refsource_CONFIRMThird Party Advisory
- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html x_refsource_CONFIRMVendor Advisory
- http://www.prnewswire.com/news-releases/mitnick-attack-reappears-at-geekpwn-macau-contest-300270779.html x_refsource_MISCTechnical Description
- http://www.securityfocus.com/bid/91704 vdb-entryx_refsource_BID
- http://www.securitytracker.com/id/1036625 vdb-entryx_refsource_SECTRACK
- http://www.ubuntu.com/usn/USN-3070-1 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3070-2 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3070-3 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3070-4 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3071-1 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3071-2 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3072-1 vendor-advisoryx_refsource_UBUNTU
- http://www.ubuntu.com/usn/USN-3072-2 vendor-advisoryx_refsource_UBUNTU
- https://access.redhat.com/security/cve/CVE-2016-5696 Vendor Advisory
- https://bto.bluecoat.com/security-advisory/sa131 x_refsource_CONFIRM
- https://bugzilla.redhat.com/show_bug.cgi?id=1354708 x_refsource_CONFIRMIssue Tracking
- https://github.com/Gnoxter/mountain_goat x_refsource_MISCExploitThird Party Advisory
- https://github.com/torvalds/linux/commit/75ff39ccc1bd5d3c455b6822ab09e533c551f758 x_refsource_CONFIRMIssue TrackingPatch
- https://kc.mcafee.com/corporate/index?page=content&id=SB10167 x_refsource_CONFIRM
- https://nvd.nist.gov/vuln/detail/CVE-2016-5696
- https://security.paloaltonetworks.com/CVE-2016-5696 x_refsource_CONFIRM
- https://www.arista.com/en/support/advisories-notices/security-advisories/1461-security-advisory-23 x_refsource_MISC
- https://www.cve.org/CVERecord?id=CVE-2016-5696
- https://www.usenix.org/system/files/conference/usenixsecurity16/sec16_paper_cao.pdf x_refsource_MISCTechnical Description
Change history (0)
No recorded changes yet.