SHA-1 is not collision resistant, which makes it easier for context-dependent attackers to conduct spoofing attacks, as demonstrated by attacks on the use of SHA-1 in TLS 1.2
Published Oct 14, 2016
5.9
MEDIUMCVSS 3.1
EPSS 0.94%
Description
SHA-1 is not collision resistant, which makes it easier for context-dependent attackers to conduct spoofing attacks, as demonstrated by attacks on the use of SHA-1 in TLS 1.2. NOTE: this CVE exists to provide a common identifier for referencing this SHA-1 issue; the existence of an identifier is not, by itself, a technology recommendation.
Affected products
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
AV:N/AC:M/Au:N/C:P/I:N/A:N
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
PartialDecision
n/aAssessed May 22, 2026 · SSVC 2.0.3
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 (11 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.94% (0.00938) | 59.47th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.94% (0.00938) | 56.09th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.11% (0.00112) | 27.36th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.31% (0.00306) | 70.62th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.31% (0.00306) | 68.98th | v3 (v2023.03.01) |
| Dec 7, 2023 | 0.31% (0.00306) | 66.42th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.27% (0.00270) | 62.68th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.54% (0.01537) | 74.52th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.54% (0.01537) | 74.48th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.54% (0.01537) | 72.41th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.54% (0.01537) | 51.33th | v2 (v2022.01.01) |
References (11)
- http://ia.cr/2007/474 x_refsource_MISCThird Party Advisory
- http://shattered.io/ x_refsource_MISC
- http://www.cwi.nl/news/2017/cwi-and-google-announce-first-collision-industry-security-standard-sha-1 x_refsource_MISC
- http://www.securityfocus.com/bid/12577 vdb-entryx_refsource_BID
- https://arstechnica.com/security/2017/02/at-deaths-door-for-years-widely-used-sha1-function-is-now-dead/ x_refsource_MISC
- https://kc.mcafee.com/corporate/index?page=content&id=SB10340 x_refsource_CONFIRM
- https://security.googleblog.com/2015/12/an-update-on-sha-1-certificates-in.html x_refsource_MISCThird Party Advisory
- https://security.googleblog.com/2017/02/announcing-first-sha1-collision.html x_refsource_MISC
- https://sites.google.com/site/itstheshappening x_refsource_MISCThird Party Advisory
- https://www.schneier.com/blog/archives/2005/02/sha1_broken.html x_refsource_MISCThird Party Advisory
- https://www.schneier.com/blog/archives/2005/08/new_cryptanalyt.html x_refsource_MISCThird Party Advisory
| Link | Providers | Tags |
|---|---|---|
| http://ia.cr/2007/474 | x_refsource_MISCThird Party Advisory | |
| http://shattered.io/ | x_refsource_MISC | |
| http://www.cwi.nl/news/2017/cwi-and-google-announce-first-collision-industry-security-standard-sha-1 | x_refsource_MISC | |
| http://www.securityfocus.com/bid/12577 | vdb-entryx_refsource_BID | |
| https://arstechnica.com/security/2017/02/at-deaths-door-for-years-widely-used-sha1-function-is-now-dead/ | x_refsource_MISC | |
| https://kc.mcafee.com/corporate/index?page=content&id=SB10340 | x_refsource_CONFIRM | |
| https://security.googleblog.com/2015/12/an-update-on-sha-1-certificates-in.html | x_refsource_MISCThird Party Advisory | |
| https://security.googleblog.com/2017/02/announcing-first-sha1-collision.html | x_refsource_MISC | |
| https://sites.google.com/site/itstheshappening | x_refsource_MISCThird Party Advisory | |
| https://www.schneier.com/blog/archives/2005/02/sha1_broken.html | x_refsource_MISCThird Party Advisory | |
| https://www.schneier.com/blog/archives/2005/08/new_cryptanalyt.html | x_refsource_MISCThird Party Advisory |
Change history (0)
No recorded changes yet.