nss: TLS 1.3 HelloRetryRequest downgrade request sets client into invalid state
Published Jan 8, 2020
6.5
MEDIUMCVSS 3.1
EPSS 1.34%
Description
After a HelloRetryRequest has been sent, the client may negotiate a lower protocol that TLS 1.3, resulting in an invalid state transition in the TLS State Machine. If the client gets into this state, incoming Application Data records will be ignored. This vulnerability affects Firefox < 72.
Affected products
-
- Version before 72StatusaffectedConstraints-
- Version
Configuration 2
- 16.04
- 18.04
- 19.04
- 19.10
- 20.04
Configuration 3
- 10.0
No data.
Red Hat Enterprise Linux 7
nspr-0:4.25.0-2.el7_9
Fixed · RHSA-2020:4076
Red Hat Enterprise Linux 7
nss-0:3.53.1-3.el7_9
Fixed · RHSA-2020:4076
Red Hat Enterprise Linux 7
nss-softokn-0:3.53.1-6.el7_9
Fixed · RHSA-2020:4076
Red Hat Enterprise Linux 7
nss-util-0:3.53.1-1.el7_9
Fixed · RHSA-2020:4076
Red Hat Enterprise Linux 8
nspr-0:4.25.0-2.el8_2
Fixed · RHSA-2020:3280
Red Hat Enterprise Linux 8
nss-0:3.53.1-11.el8_2
Fixed · RHSA-2020:3280
Red Hat OpenShift Do
openshiftdo/odo-init-image-rhel7:1.1.3-2
Fixed · RHSA-2021:0949
Red Hat Enterprise Linux 5
nss
Out of support scope
Red Hat Enterprise Linux 6
nss
Out of support scope
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | nspr-0:4.25.0-2.el7_9 | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux 7 | nss-0:3.53.1-3.el7_9 | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux 7 | nss-softokn-0:3.53.1-6.el7_9 | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux 7 | nss-util-0:3.53.1-1.el7_9 | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux 8 | nspr-0:4.25.0-2.el8_2 | Fixed | RHSA-2020:3280 |
| Red Hat Enterprise Linux 8 | nss-0:3.53.1-11.el8_2 | Fixed | RHSA-2020:3280 |
| Red Hat OpenShift Do | openshiftdo/odo-init-image-rhel7:1.1.3-2 | Fixed | RHSA-2021:0949 |
| Red Hat Enterprise Linux 5 | nss | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | nss | Out of support scope | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This flaw causes the client to hang when there is a downgrade attempt. Therefore no actual protocol downgrade occurs.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
1 other source (Red Hat) ▾
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
No CVSS v3.0 score for this CVE.
AV:N/AC:M/Au:N/C:N/I:P/A:N
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
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Table of values (17 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 1.34% (0.01340) | 70.29th | v5 (v2026.06.15) |
| Jun 15, 2026 | 1.34% (0.01340) | 67.52th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.17% (0.00166) | 35.22th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.22% (0.00216) | 60.48th | v3 (v2023.03.01) |
| May 3, 2024 | 0.22% (0.00216) | 59.40th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.31% (0.00307) | 69.06th | v3 (v2023.03.01) |
| Nov 12, 2023 | 0.31% (0.00307) | 66.52th | v3 (v2023.03.01) |
| Oct 28, 2023 | 0.32% (0.00316) | 67.03th | v3 (v2023.03.01) |
| Sep 3, 2023 | 0.26% (0.00264) | 63.34th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.34% (0.00343) | 66.95th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.02% (0.01018) | 40.69th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.02% (0.01018) | 36.86th | v2 (v2022.01.01) |
| Feb 4, 2022 | 4.13% (0.04134) | 68.25th | v2 (v2022.01.01) |
| Feb 3, 2022 | 5.36% (0.05363) | 79.74th | v1 |
| Jan 6, 2022 | 5.36% (0.05363) | 79.54th | v1 |
| Jan 5, 2022 | 1.25% (0.01247) | 69.74th | v5 (v2026.06.15) |
| Apr 14, 2021 | 1.25% (0.01247) | 0.00th | v1 |
References (10)
- https://access.redhat.com/security/cve/CVE-2019-17023 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1590001 x_refsource_MISCIssue TrackingPermissions Required
- https://bugzilla.redhat.com/show_bug.cgi?id=1791225 Issue Tracking
- https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.49_release_notes
- https://nvd.nist.gov/vuln/detail/CVE-2019-17023
- https://usn.ubuntu.com/4234-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/4397-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2019-17023
- https://www.debian.org/security/2020/dsa-4726 vendor-advisoryx_refsource_DEBIANThird Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2020-01/ x_refsource_CONFIRMVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2019-17023 | Vendor Advisory | |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1590001 | x_refsource_MISCIssue TrackingPermissions Required | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1791225 | Issue Tracking | |
| https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.49_release_notes | ||
| https://nvd.nist.gov/vuln/detail/CVE-2019-17023 | ||
| https://usn.ubuntu.com/4234-1/ | vendor-advisoryx_refsource_UBUNTUThird Party Advisory | |
| https://usn.ubuntu.com/4397-1/ | vendor-advisoryx_refsource_UBUNTUThird Party Advisory | |
| https://www.cve.org/CVERecord?id=CVE-2019-17023 | ||
| https://www.debian.org/security/2020/dsa-4726 | vendor-advisoryx_refsource_DEBIANThird Party Advisory | |
| https://www.mozilla.org/security/advisories/mfsa2020-01/ | x_refsource_CONFIRMVendor Advisory |
Change history (0)
No recorded changes yet.