python: DOS via regular expression backtracking in difflib.IS_LINE_JUNK method in difflib
Published Jun 19, 2018
7.5
HIGHCVSS 3.0
EPSS 4.92%
Description
python before versions 2.7.15, 3.4.9, 3.5.6rc1, 3.6.5rc1 and 3.7.0 is vulnerable to catastrophic backtracking in the difflib.IS_LINE_JUNK method. An attacker could use this flaw to cause denial of service.
Affected products
- Vendor n/a Product Python Defaultn/a
- Version python 2.7.15StatusaffectedConstraints-
- Version python 3.4.9StatusaffectedConstraints-
- Version python 3.5.6StatusaffectedConstraints-
- Version python 3.7.0StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n/a | Python | n/a |
|
Configuration 1
- < 2.7.15
- ≥ 3.0 · < 3.4.9
- ≥ 3.5.0 · ≤ 3.5.5
- ≥ 3.6 · ≤ 3.6.4
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
- 3.7.0
Configuration 2
- 8.0
- 9.0
Configuration 3
- 3.3
- 7.0
- 7.0
- 7.0
Configuration 4
- 12.04
- 14.04
- 16.04
- 18.04
Configuration 5
- 28
- 29
- 30
No data.
Red Hat Enterprise Linux 7
python-0:2.7.5-76.el7
Fixed · RHSA-2018:3041
Red Hat Enterprise Linux 7.4 Advanced Update Support
python-0:2.7.5-63.el7_4
Fixed · RHSA-2020:1346
Red Hat Enterprise Linux 7.4 Telco Extended Update Support
python-0:2.7.5-63.el7_4
Fixed · RHSA-2020:1346
Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions
python-0:2.7.5-63.el7_4
Fixed · RHSA-2020:1346
Red Hat Enterprise Linux 7.5 Extended Update Support
python-0:2.7.5-74.el7_5
Fixed · RHSA-2020:1268
Red Hat Software Collections for Red Hat Enterprise Linux 6
python27-python-0:2.7.16-4.el6
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 6
python27-python-jinja2-0:2.6-12.el6
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 6
rh-python36-python-0:3.6.9-2.el6
Fixed · RHSA-2019:3725
Red Hat Software Collections for Red Hat Enterprise Linux 7
python27-python-0:2.7.16-4.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7
python27-python-jinja2-0:2.6-15.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7
rh-python36-python-0:3.6.9-2.el7
Fixed · RHSA-2019:3725
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
python27-python-0:2.7.16-4.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS
python27-python-jinja2-0:2.6-15.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
python27-python-0:2.7.16-4.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
python27-python-jinja2-0:2.6-15.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS
rh-python36-python-0:3.6.9-2.el7
Fixed · RHSA-2019:3725
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
python27-python-0:2.7.16-4.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
python27-python-jinja2-0:2.6-15.el7
Fixed · RHSA-2019:1260
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS
rh-python36-python-0:3.6.9-2.el7
Fixed · RHSA-2019:3725
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS
rh-python36-python-0:3.6.9-2.el7
Fixed · RHSA-2019:3725
Red Hat Enterprise Linux 5
python
Will not fix
Red Hat Enterprise Linux 6
python
Will not fix
Red Hat Software Collections
rh-python34-python
Will not fix
Red Hat Software Collections
rh-python35-python
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | python-0:2.7.5-76.el7 | Fixed | RHSA-2018:3041 |
| Red Hat Enterprise Linux 7.4 Advanced Update Support | python-0:2.7.5-63.el7_4 | Fixed | RHSA-2020:1346 |
| Red Hat Enterprise Linux 7.4 Telco Extended Update Support | python-0:2.7.5-63.el7_4 | Fixed | RHSA-2020:1346 |
| Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions | python-0:2.7.5-63.el7_4 | Fixed | RHSA-2020:1346 |
| Red Hat Enterprise Linux 7.5 Extended Update Support | python-0:2.7.5-74.el7_5 | Fixed | RHSA-2020:1268 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | python27-python-0:2.7.16-4.el6 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | python27-python-jinja2-0:2.6-12.el6 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | rh-python36-python-0:3.6.9-2.el6 | Fixed | RHSA-2019:3725 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | python27-python-0:2.7.16-4.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | python27-python-jinja2-0:2.6-15.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-python36-python-0:3.6.9-2.el7 | Fixed | RHSA-2019:3725 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | python27-python-0:2.7.16-4.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | python27-python-jinja2-0:2.6-15.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | python27-python-0:2.7.16-4.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | python27-python-jinja2-0:2.6-15.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS | rh-python36-python-0:3.6.9-2.el7 | Fixed | RHSA-2019:3725 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | python27-python-0:2.7.16-4.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | python27-python-jinja2-0:2.6-15.el7 | Fixed | RHSA-2019:1260 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS | rh-python36-python-0:3.6.9-2.el7 | Fixed | RHSA-2019:3725 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | rh-python36-python-0:3.6.9-2.el7 | Fixed | RHSA-2019:3725 |
| Red Hat Enterprise Linux 5 | python | Will not fix | n/a |
| Red Hat Enterprise Linux 6 | python | Will not fix | n/a |
| Red Hat Software Collections | rh-python34-python | Will not fix | n/a |
| Red Hat Software Collections | rh-python35-python | Will not fix | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
AV:N/AC:L/Au:N/C:N/I:N/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
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 (18 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 4.92% (0.04916) | 91.84th | v5 (v2026.06.15) |
| Jun 15, 2026 | 4.98% (0.04979) | 91.06th | v5 (v2026.06.15) |
| Nov 21, 2025 | 0.93% (0.00928) | 75.36th | v4 (v2025.03.14) |
| Nov 18, 2025 | 6.32% (0.06319) | 90.03th | v4 (v2025.03.14) |
| May 30, 2025 | 1.64% (0.01643) | 81.05th | v4 (v2025.03.14) |
| Mar 17, 2025 | 3.71% (0.03707) | 87.17th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.63% (0.00634) | 79.80th | v3 (v2023.03.01) |
| Apr 17, 2024 | 0.63% (0.00634) | 78.84th | v3 (v2023.03.01) |
| Jan 13, 2024 | 0.63% (0.00634) | 76.83th | v3 (v2023.03.01) |
| Dec 20, 2023 | 0.81% (0.00808) | 79.81th | v3 (v2023.03.01) |
| Nov 10, 2023 | 0.71% (0.00707) | 78.14th | v3 (v2023.03.01) |
| Nov 8, 2023 | 0.83% (0.00835) | 80.04th | v3 (v2023.03.01) |
| Sep 3, 2023 | 0.69% (0.00687) | 77.58th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.50% (0.00501) | 72.67th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.69% (0.02686) | 82.85th | v2 (v2022.01.01) |
| Feb 4, 2022 | 2.69% (0.02686) | 62.66th | v2 (v2022.01.01) |
| Feb 3, 2022 | 5.51% (0.05507) | 79.91th | v5 (v2026.06.15) |
| Apr 14, 2021 | 5.51% (0.05507) | 0.00th | v1 |
References (26)
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html vendor-advisoryx_refsource_SUSE
- http://www.securitytracker.com/id/1042001 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- https://access.redhat.com/errata/RHBA-2019:0327 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2018:3041 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2018:3505 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2019:1260 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2019:3725 vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2018-1061 Vendor Advisory
- https://bugs.python.org/issue32981 x_refsource_CONFIRMVendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1549192 Issue Tracking
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1061 x_refsource_CONFIRMIssue Tracking
- https://docs.python.org/3.5/whatsnew/changelog.html#python-3-5-6-release-candidate-1 x_refsource_CONFIRMVendor Advisory
- https://docs.python.org/3.6/whatsnew/changelog.html#python-3-6-5-final
- https://docs.python.org/3.6/whatsnew/changelog.html#python-3-6-5-release-candidate-1 x_refsource_CONFIRMVendor Advisory
- https://lists.debian.org/debian-lts-announce/2018/09/msg00030.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2018/09/msg00031.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/46PVWY5LFP4BRPG3BVQ5QEEFYBVEXHCK/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AEZ5IQT7OF7Q2NCGIVABOWYGKO7YU3NJ/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JSKPGPZQNTAULHW4UH63KGOOUIDE4RRB/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2018-1061
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbst03951en_us x_refsource_CONFIRM
- https://usn.ubuntu.com/3817-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/3817-2/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-1061
- https://www.debian.org/security/2018/dsa-4306 vendor-advisoryx_refsource_DEBIANThird Party Advisory
- https://www.debian.org/security/2018/dsa-4307 vendor-advisoryx_refsource_DEBIANThird Party Advisory
Change history (0)
No recorded changes yet.