CVE-2025-21647

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Source
https://nvd.nist.gov/vuln/detail/CVE-2025-21647
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21647.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-21647
Downstream
Related
Published
2025-01-19T10:18:04Z
Modified
2025-10-17T22:59:29.515070Z
Summary
sched: sch_cake: add bounds checks to host bulk flow fairness counts
Details

In the Linux kernel, the following vulnerability has been resolved:

sched: sch_cake: add bounds checks to host bulk flow fairness counts

Even though we fixed a logic error in the commit cited below, syzbot still managed to trigger an underflow of the per-host bulk flow counters, leading to an out of bounds memory access.

To avoid any such logic errors causing out of bounds memory accesses, this commit factors out all accesses to the per-host bulk flow counters to a series of helpers that perform bounds-checking before any increments and decrements. This also has the benefit of improving readability by moving the conditional checks for the flow mode into these helpers, instead of having them spread out throughout the code (which was the cause of the original logic error).

As part of this change, the flow quantum calculation is consolidated into a helper function, which means that the dithering applied to the ost load scaling is now applied both in the DRR rotation and when a sparse flow's quantum is first initiated. The only user-visible effect of this is that the maximum packet size that can be sent while a flow stays sparse will now vary with +/- one byte in some cases. This should not make a noticeable difference in practice, and thus it's not worth complicating the code to preserve the old behaviour.

References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4a4eeefa514db570be025ab46d779af180e2c9bb
Fixed
44fe1efb4961c1a5ccab16bb579dfc6b308ad58b
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
7725152b54d295b7da5e34c2f419539b30d017bd
Fixed
b1a1743aaa4906c41c426eda97e2e2586f79246d
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
cde71a5677971f4f1b69b25e854891dbe78066a4
Fixed
bb0245fa72b783cb23a9949c5048781341e91423
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
549e407569e08459d16122341d332cb508024094
Fixed
a777e06dfc72bed73c05dcb437d7c27ad5f90f3f
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
d4a9039a7b3d8005b90c7b1a55a306444f0e5447
Fixed
27202e2e8721c3b23831563c36ed5ac7818641ba
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
546ea84d07e3e324644025e2aae2d12ea4c5896e
Fixed
91bb18950b88f955838ec0c1d97f74d135756dc7
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
546ea84d07e3e324644025e2aae2d12ea4c5896e
Fixed
737d4d91d35b5f7fa5bb442651472277318b0bfd
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
d7c01c0714c04431b5e18cf17a9ea68a553d1c3c

Affected versions

v2.*

v2.6.12
v2.6.12-rc2
v2.6.12-rc3
v2.6.12-rc4
v2.6.12-rc5
v2.6.12-rc6
v2.6.13
v2.6.13-rc1
v2.6.13-rc2
v2.6.13-rc3
v2.6.13-rc4
v2.6.13-rc5
v2.6.13-rc6
v2.6.13-rc7
v2.6.14
v2.6.14-rc1
v2.6.14-rc2
v2.6.14-rc3
v2.6.14-rc4
v2.6.14-rc5
v2.6.15
v2.6.15-rc1
v2.6.15-rc2
v2.6.15-rc3
v2.6.15-rc4
v2.6.15-rc5
v2.6.15-rc6
v2.6.15-rc7
v2.6.16
v2.6.16-rc1
v2.6.16-rc2
v2.6.16-rc3
v2.6.16-rc4
v2.6.16-rc5
v2.6.16-rc6
v2.6.17
v2.6.17-rc1
v2.6.17-rc2
v2.6.17-rc3
v2.6.17-rc4
v2.6.17-rc5
v2.6.17-rc6
v2.6.18
v2.6.18-rc1
v2.6.18-rc2
v2.6.18-rc3
v2.6.18-rc4
v2.6.18-rc5
v2.6.18-rc6
v2.6.18-rc7
v2.6.19
v2.6.19-rc1
v2.6.19-rc2
v2.6.19-rc3
v2.6.19-rc4
v2.6.19-rc5
v2.6.19-rc6
v2.6.20
v2.6.20-rc1
v2.6.20-rc2
v2.6.20-rc3
v2.6.20-rc4
v2.6.20-rc5
v2.6.20-rc6
v2.6.20-rc7
v2.6.21
v2.6.21-rc1
v2.6.21-rc2
v2.6.21-rc3
v2.6.21-rc4
v2.6.21-rc5
v2.6.21-rc6
v2.6.21-rc7
v2.6.22
v2.6.22-rc1
v2.6.22-rc2
v2.6.22-rc3
v2.6.22-rc4
v2.6.22-rc5
v2.6.22-rc6
v2.6.22-rc7
v2.6.23
v2.6.23-rc1
v2.6.23-rc2
v2.6.23-rc3
v2.6.23-rc4
v2.6.23-rc5
v2.6.23-rc6
v2.6.23-rc7
v2.6.23-rc8
v2.6.23-rc9
v2.6.24
v2.6.24-rc1
v2.6.24-rc2
v2.6.24-rc3
v2.6.24-rc4
v2.6.24-rc5
v2.6.24-rc6
v2.6.24-rc7
v2.6.24-rc8
v2.6.25
v2.6.25-rc1
v2.6.25-rc2
v2.6.25-rc3
v2.6.25-rc4
v2.6.25-rc5
v2.6.25-rc6
v2.6.25-rc7
v2.6.25-rc8
v2.6.25-rc9
v2.6.26
v2.6.26-rc1
v2.6.26-rc2
v2.6.26-rc3
v2.6.26-rc4
v2.6.26-rc5
v2.6.26-rc6
v2.6.26-rc7
v2.6.26-rc8
v2.6.26-rc9
v2.6.27
v2.6.27-rc1
v2.6.27-rc2
v2.6.27-rc3
v2.6.27-rc4
v2.6.27-rc5
v2.6.27-rc6
v2.6.27-rc7
v2.6.27-rc8
v2.6.27-rc9
v2.6.28
v2.6.28-rc1
v2.6.28-rc2
v2.6.28-rc3
v2.6.28-rc4
v2.6.28-rc5
v2.6.28-rc6
v2.6.28-rc7
v2.6.28-rc8
v2.6.28-rc9
v2.6.29
v2.6.29-rc1
v2.6.29-rc2
v2.6.29-rc3
v2.6.29-rc4
v2.6.29-rc5
v2.6.29-rc6
v2.6.29-rc7
v2.6.29-rc8
v2.6.30
v2.6.30-rc1
v2.6.30-rc2
v2.6.30-rc3
v2.6.30-rc4
v2.6.30-rc5
v2.6.30-rc6
v2.6.30-rc7
v2.6.30-rc8
v2.6.31
v2.6.31-rc1
v2.6.31-rc2
v2.6.31-rc3
v2.6.31-rc4
v2.6.31-rc5
v2.6.31-rc6
v2.6.31-rc7
v2.6.31-rc8
v2.6.31-rc9
v2.6.32
v2.6.32-rc1
v2.6.32-rc2
v2.6.32-rc3
v2.6.32-rc4
v2.6.32-rc5
v2.6.32-rc6
v2.6.32-rc7
v2.6.32-rc8
v2.6.33
v2.6.33-rc1
v2.6.33-rc2
v2.6.33-rc3
v2.6.33-rc4
v2.6.33-rc5
v2.6.33-rc6
v2.6.33-rc7
v2.6.33-rc8
v2.6.34
v2.6.34-rc1
v2.6.34-rc2
v2.6.34-rc3
v2.6.34-rc4
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v2.6.35
v2.6.35-rc1
v2.6.35-rc2
v2.6.35-rc3
v2.6.35-rc4
v2.6.35-rc5
v2.6.35-rc6
v2.6.36
v2.6.36-rc1
v2.6.36-rc2
v2.6.36-rc3
v2.6.36-rc4
v2.6.36-rc5
v2.6.36-rc6
v2.6.36-rc7
v2.6.36-rc8
v2.6.37
v2.6.37-rc1
v2.6.37-rc2
v2.6.37-rc3
v2.6.37-rc4
v2.6.37-rc5
v2.6.37-rc6
v2.6.37-rc7
v2.6.37-rc8
v2.6.38
v2.6.38-rc1
v2.6.38-rc2
v2.6.38-rc3
v2.6.38-rc4
v2.6.38-rc5
v2.6.38-rc6
v2.6.38-rc7
v2.6.38-rc8
v2.6.39
v2.6.39-rc1
v2.6.39-rc2
v2.6.39-rc3
v2.6.39-rc4
v2.6.39-rc5
v2.6.39-rc6
v2.6.39-rc7

v3.*

v3.0
v3.0-rc1
v3.0-rc2
v3.0-rc3
v3.0-rc4
v3.0-rc5
v3.0-rc6
v3.0-rc7
v3.1
v3.1-rc1
v3.1-rc10
v3.1-rc2
v3.1-rc3
v3.1-rc4
v3.1-rc5
v3.1-rc6
v3.1-rc7
v3.1-rc8
v3.1-rc9
v3.10
v3.10-rc1
v3.10-rc2
v3.10-rc3
v3.10-rc4
v3.10-rc5
v3.10-rc6
v3.10-rc7
v3.11
v3.11-rc1
v3.11-rc2
v3.11-rc3
v3.11-rc4
v3.11-rc5
v3.11-rc6
v3.11-rc7
v3.12
v3.12-rc1
v3.12-rc2
v3.12-rc3
v3.12-rc4
v3.12-rc5
v3.12-rc6
v3.12-rc7
v3.13
v3.13-rc1
v3.13-rc2
v3.13-rc3
v3.13-rc4
v3.13-rc5
v3.13-rc6
v3.13-rc7
v3.13-rc8
v3.14
v3.14-rc1
v3.14-rc2
v3.14-rc3
v3.14-rc4
v3.14-rc5
v3.14-rc6
v3.14-rc7
v3.14-rc8
v3.15
v3.15-rc1
v3.15-rc2
v3.15-rc3
v3.15-rc4
v3.15-rc5
v3.15-rc6
v3.15-rc7
v3.15-rc8
v3.16
v3.16-rc1
v3.16-rc2
v3.16-rc3
v3.16-rc4
v3.16-rc5
v3.16-rc6
v3.16-rc7
v3.17
v3.17-rc1
v3.17-rc2
v3.17-rc3
v3.17-rc4
v3.17-rc5
v3.17-rc6
v3.17-rc7
v3.18
v3.18-rc1
v3.18-rc2
v3.18-rc3
v3.18-rc4
v3.18-rc5
v3.18-rc6
v3.18-rc7
v3.19
v3.19-rc1
v3.19-rc2
v3.19-rc3
v3.19-rc4
v3.19-rc5
v3.19-rc6
v3.19-rc7
v3.2
v3.2-rc1
v3.2-rc2
v3.2-rc3
v3.2-rc4
v3.2-rc5
v3.2-rc6
v3.2-rc7
v3.3
v3.3-rc1
v3.3-rc2
v3.3-rc3
v3.3-rc4
v3.3-rc5
v3.3-rc6
v3.3-rc7
v3.4
v3.4-rc1
v3.4-rc2
v3.4-rc3
v3.4-rc4
v3.4-rc5
v3.4-rc6
v3.4-rc7
v3.5
v3.5-rc1
v3.5-rc2
v3.5-rc3
v3.5-rc4
v3.5-rc5
v3.5-rc6
v3.5-rc7
v3.6
v3.6-rc1
v3.6-rc2
v3.6-rc3
v3.6-rc4
v3.6-rc5
v3.6-rc6
v3.6-rc7
v3.7
v3.7-rc1
v3.7-rc2
v3.7-rc3
v3.7-rc4
v3.7-rc5
v3.7-rc6
v3.7-rc7
v3.7-rc8
v3.8
v3.8-rc1
v3.8-rc2
v3.8-rc3
v3.8-rc4
v3.8-rc5
v3.8-rc6
v3.8-rc7
v3.9
v3.9-rc1
v3.9-rc2
v3.9-rc3
v3.9-rc4
v3.9-rc5
v3.9-rc6
v3.9-rc7
v3.9-rc8

v4.*

v4.0
v4.0-rc1
v4.0-rc2
v4.0-rc3
v4.0-rc4
v4.0-rc5
v4.0-rc6
v4.0-rc7
v4.1
v4.1-rc1
v4.1-rc2
v4.1-rc3
v4.1-rc4
v4.1-rc5
v4.1-rc6
v4.1-rc7
v4.1-rc8
v4.10
v4.10-rc1
v4.10-rc2
v4.10-rc3
v4.10-rc4
v4.10-rc5
v4.10-rc6
v4.10-rc7
v4.10-rc8
v4.11
v4.11-rc1
v4.11-rc2
v4.11-rc3
v4.11-rc4
v4.11-rc5
v4.11-rc6
v4.11-rc7
v4.11-rc8
v4.12
v4.12-rc1
v4.12-rc2
v4.12-rc3
v4.12-rc4
v4.12-rc5
v4.12-rc6
v4.12-rc7
v4.13
v4.13-rc1
v4.13-rc2
v4.13-rc3
v4.13-rc4
v4.13-rc5
v4.13-rc6
v4.13-rc7
v4.14
v4.14-rc1
v4.14-rc2
v4.14-rc3
v4.14-rc4
v4.14-rc5
v4.14-rc6
v4.14-rc7
v4.14-rc8
v4.15
v4.15-rc1
v4.15-rc2
v4.15-rc3
v4.15-rc4
v4.15-rc5
v4.15-rc6
v4.15-rc7
v4.15-rc8
v4.15-rc9
v4.16
v4.16-rc1
v4.16-rc2
v4.16-rc3
v4.16-rc4
v4.16-rc5
v4.16-rc6
v4.16-rc7
v4.17
v4.17-rc1
v4.17-rc2
v4.17-rc3
v4.17-rc4
v4.17-rc5
v4.17-rc6
v4.17-rc7
v4.18
v4.18-rc1
v4.18-rc2
v4.18-rc3
v4.18-rc4
v4.18-rc5
v4.18-rc6
v4.18-rc7
v4.18-rc8
v4.19
v4.19-rc1
v4.19-rc2
v4.19-rc3
v4.19-rc4
v4.19-rc5
v4.19-rc6
v4.19-rc7
v4.19-rc8
v4.2
v4.2-rc1
v4.2-rc2
v4.2-rc3
v4.2-rc4
v4.2-rc5
v4.2-rc6
v4.2-rc7
v4.2-rc8
v4.20
v4.20-rc1
v4.20-rc2
v4.20-rc3
v4.20-rc4
v4.20-rc5
v4.20-rc6
v4.20-rc7
v4.3
v4.3-rc1
v4.3-rc2
v4.3-rc3
v4.3-rc4
v4.3-rc5
v4.3-rc6
v4.3-rc7
v4.4
v4.4-rc1
v4.4-rc2
v4.4-rc3
v4.4-rc4
v4.4-rc5
v4.4-rc6
v4.4-rc7
v4.4-rc8
v4.5
v4.5-rc1
v4.5-rc2
v4.5-rc3
v4.5-rc4
v4.5-rc5
v4.5-rc6
v4.5-rc7
v4.6
v4.6-rc1
v4.6-rc2
v4.6-rc3
v4.6-rc4
v4.6-rc5
v4.6-rc6
v4.6-rc7
v4.7
v4.7-rc1
v4.7-rc2
v4.7-rc3
v4.7-rc4
v4.7-rc5
v4.7-rc6
v4.7-rc7
v4.8
v4.8-rc1
v4.8-rc2
v4.8-rc3
v4.8-rc4
v4.8-rc5
v4.8-rc6
v4.8-rc7
v4.8-rc8
v4.9
v4.9-rc1
v4.9-rc2
v4.9-rc3
v4.9-rc4
v4.9-rc5
v4.9-rc6
v4.9-rc7
v4.9-rc8

v5.*

v5.0
v5.0-rc1
v5.0-rc2
v5.0-rc3
v5.0-rc4
v5.0-rc5
v5.0-rc6
v5.0-rc7
v5.0-rc8
v5.1
v5.1-rc1
v5.1-rc2
v5.1-rc3
v5.1-rc4
v5.1-rc5
v5.1-rc6
v5.1-rc7
v5.10
v5.10-rc1
v5.10-rc2
v5.10-rc3
v5.10-rc4
v5.10-rc5
v5.10-rc6
v5.10-rc7
v5.10.226
v5.10.227
v5.10.228
v5.10.229
v5.10.230
v5.10.231
v5.10.232
v5.10.233
v5.10.234
v5.11
v5.11-rc1
v5.11-rc2
v5.11-rc3
v5.11-rc4
v5.11-rc5
v5.11-rc6
v5.11-rc7
v5.12
v5.12-rc1
v5.12-rc1-dontuse
v5.12-rc2
v5.12-rc3
v5.12-rc4
v5.12-rc5
v5.12-rc6
v5.12-rc7
v5.12-rc8
v5.13
v5.13-rc1
v5.13-rc2
v5.13-rc3
v5.13-rc4
v5.13-rc5
v5.13-rc6
v5.13-rc7
v5.14
v5.14-rc1
v5.14-rc2
v5.14-rc3
v5.14-rc4
v5.14-rc5
v5.14-rc6
v5.14-rc7
v5.15
v5.15-rc1
v5.15-rc2
v5.15-rc3
v5.15-rc4
v5.15-rc5
v5.15-rc6
v5.15-rc7
v5.15.167
v5.15.168
v5.15.169
v5.15.170
v5.15.171
v5.15.172
v5.15.173
v5.15.174
v5.15.175
v5.15.176
v5.15.177
v5.15.178
v5.16
v5.16-rc1
v5.16-rc2
v5.16-rc3
v5.16-rc4
v5.16-rc5
v5.16-rc6
v5.16-rc7
v5.16-rc8
v5.17
v5.17-rc1
v5.17-rc2
v5.17-rc3
v5.17-rc4
v5.17-rc5
v5.17-rc6
v5.17-rc7
v5.17-rc8
v5.18
v5.18-rc1
v5.18-rc2
v5.18-rc3
v5.18-rc4
v5.18-rc5
v5.18-rc6
v5.18-rc7
v5.19
v5.19-rc1
v5.19-rc2
v5.19-rc3
v5.19-rc4
v5.19-rc5
v5.19-rc6
v5.19-rc7
v5.19-rc8
v5.2
v5.2-rc1
v5.2-rc2
v5.2-rc3
v5.2-rc4
v5.2-rc5
v5.2-rc6
v5.2-rc7
v5.3
v5.3-rc1
v5.3-rc2
v5.3-rc3
v5.3-rc4
v5.3-rc5
v5.3-rc6
v5.3-rc7
v5.3-rc8
v5.4
v5.4-rc1
v5.4-rc2
v5.4-rc3
v5.4-rc4
v5.4-rc5
v5.4-rc6
v5.4-rc7
v5.4-rc8
v5.4.284
v5.4.285
v5.4.286
v5.4.287
v5.4.288
v5.4.289
v5.4.290
v5.5
v5.5-rc1
v5.5-rc2
v5.5-rc3
v5.5-rc4
v5.5-rc5
v5.5-rc6
v5.5-rc7
v5.6
v5.6-rc1
v5.6-rc2
v5.6-rc3
v5.6-rc4
v5.6-rc5
v5.6-rc6
v5.6-rc7
v5.7
v5.7-rc1
v5.7-rc2
v5.7-rc3
v5.7-rc4
v5.7-rc5
v5.7-rc6
v5.7-rc7
v5.8
v5.8-rc1
v5.8-rc2
v5.8-rc3
v5.8-rc4
v5.8-rc5
v5.8-rc6
v5.8-rc7
v5.9
v5.9-rc1
v5.9-rc2
v5.9-rc3
v5.9-rc4
v5.9-rc5
v5.9-rc6
v5.9-rc7
v5.9-rc8

v6.*

v6.0
v6.0-rc1
v6.0-rc2
v6.0-rc3
v6.0-rc4
v6.0-rc5
v6.0-rc6
v6.0-rc7
v6.1
v6.1-rc1
v6.1-rc2
v6.1-rc3
v6.1-rc4
v6.1-rc5
v6.1-rc6
v6.1-rc7
v6.1-rc8
v6.1.110
v6.1.111
v6.1.112
v6.1.113
v6.1.114
v6.1.115
v6.1.116
v6.1.117
v6.1.118
v6.1.119
v6.1.120
v6.1.121
v6.1.122
v6.1.123
v6.1.124
v6.10
v6.10-rc1
v6.10-rc2
v6.10-rc3
v6.10-rc4
v6.10-rc5
v6.10-rc6
v6.10-rc7
v6.10.1
v6.10.2
v6.10.3
v6.10.4
v6.10.5
v6.10.6
v6.10.7
v6.10.8
v6.10.9
v6.11
v6.11-rc6
v6.11-rc7
v6.12
v6.12-rc1
v6.12-rc2
v6.12-rc3
v6.12-rc4
v6.12-rc5
v6.12-rc6
v6.12-rc7
v6.12.1
v6.12.2
v6.12.3
v6.12.4
v6.12.5
v6.12.6
v6.12.7
v6.12.8
v6.12.9
v6.13-rc1
v6.13-rc2
v6.13-rc3
v6.13-rc4
v6.13-rc5
v6.2
v6.2-rc1
v6.2-rc2
v6.2-rc3
v6.2-rc4
v6.2-rc5
v6.2-rc6
v6.2-rc7
v6.2-rc8
v6.3
v6.3-rc1
v6.3-rc2
v6.3-rc3
v6.3-rc4
v6.3-rc5
v6.3-rc6
v6.3-rc7
v6.4
v6.4-rc1
v6.4-rc2
v6.4-rc3
v6.4-rc4
v6.4-rc5
v6.4-rc6
v6.4-rc7
v6.5
v6.5-rc1
v6.5-rc2
v6.5-rc3
v6.5-rc4
v6.5-rc5
v6.5-rc6
v6.5-rc7
v6.6
v6.6-rc1
v6.6-rc2
v6.6-rc3
v6.6-rc4
v6.6-rc5
v6.6-rc6
v6.6-rc7
v6.6.51
v6.6.52
v6.6.53
v6.6.54
v6.6.55
v6.6.56
v6.6.57
v6.6.58
v6.6.59
v6.6.60
v6.6.61
v6.6.62
v6.6.63
v6.6.64
v6.6.65
v6.6.66
v6.6.67
v6.6.68
v6.6.69
v6.6.70
v6.6.71
v6.7
v6.7-rc1
v6.7-rc2
v6.7-rc3
v6.7-rc4
v6.7-rc5
v6.7-rc6
v6.7-rc7
v6.7-rc8
v6.8
v6.8-rc1
v6.8-rc2
v6.8-rc3
v6.8-rc4
v6.8-rc5
v6.8-rc6
v6.8-rc7
v6.9
v6.9-rc1
v6.9-rc2
v6.9-rc3
v6.9-rc4
v6.9-rc5
v6.9-rc6
v6.9-rc7

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.4.291
Type
ECOSYSTEM
Events
Introduced
5.5.0
Fixed
5.10.235
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.179
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.125
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.72
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.10